Construction Scheduling With Primavera P6 Jongpil Nam
AuthorHouse™ UK Ltd. 1663 Liberty Drive Bloomington, IN 47403 USA www.authorhouse.co.uk Phone: 0800.197.4150 © 2016 Jongpil Nam. All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted by any means without the written permission of the author. All screenshots taken from the Primavera P6 PPM 8.3 (2014) are copyrighted and used with permission. Published by AuthorHouse 04/15/2016 ISBN: 978-1-5246-3049-2 (sc) ISBN: 978-1-5246-3050-8 (e) Any people depicted in stock imagery provided by Thinkstock are models, and such images are being used for illustrative purposes only. Certain stock imagery © Thinkstock. Because of the dynamic nature of the Internet, any web addresses or links contained in this book may have changed since publication and may no longer be valid. The views expressed in this work are solely those of the author and do not necessarily reflect the views of the publisher, and the publisher hereby disclaims any responsibility for them.
Preface Project scheduling is one of the vital factors that contributes to a project’s success or failure. A project schedule provides a pathway towards the completion of a project as scheduled, and continuous feedback on how the project is progressing. However, schedule controllers are often frustrated when their schedules are impeded by unexpected events, or at colleagues’ failure to comprehend their schedules correctly and communicate with schedulers efficiently. Thus, a primary concern of schedulers today involves developing comprehensive schedules as early as possible, and using them efficiently to best communicate with their clients and colleagues. Furthermore, a good schedule has to provide schedulers and project management team members with an opportunity to anticipate any risks so that the project management team can prepare countermeasures to mitigate them. This book focuses on planning and scheduling for construction projects and presents fieldsite-based best practices related to schedule management and Primavera P6, and offers strategies that utilise scheduling methodologies and tools. These strategies are based on the theory of schedule management and features of scheduling software packages, which can be applied in every field site no matter what the construction project type is. This book introduces examples and tips, as well as suggestions for developing efficient schedules and management methods that ensure immediate improvement in schedule controlling. This book is designed to be Primavera P6 user-friendly, so readers using P6 can understand P6-based schedule management with ease. This book covers all matters schedulers should know and understand regarding schedule management. It also includes the missing manuals of schedule management textbooks and Primavera P6 manuals. Therefore, I recommend that those who want to be a skilled scheduler make use of this book, along with schedule management textbooks and Primavera P6 manuals. I wish you success in schedule management. Jongpil Nam Schedule Manager, PMP
[email protected]
About the Author Jongpil Nam
He began his career at Korea Rail Network Authority in South Korea in 1995. As a scheduling engineer and project planner, he worked on the construction of the Korea High-Speed Line (an 11 billion USD project) and other sizeable railway construction projects, cooperating with the staff of Bechtel, Inc. Between 2011 and 2012, he studied for a master’s degree in Railway System Engineering and Integration at the University of Birmingham, UK. His master’s dissertation, entitled “Time Management in Railway Construction Projects”, explored efficient ways to develop and control the master schedule of railway construction projects, and earned him the University of Birmingham’s award for Best Technical Dissertation. Based on his vast experience of project schedule planning and controlling, he published a book on the subject in 2014, entitled “How Railway Systems Work”, which introduces various basic knowledge of railway and railway construction project planning and controlling methods. The book was adopted as a textbook by Woosong University in South Korea. In December 2014 and March 2015, he conducted lectures for government officials at the Egypt Railway School, which were organised by the Egyptian government. The theme of these lectures was managing construction schedules for efficient railway construction projects. His current job involves managing the master schedule of the Enhancement Programme of the national railway infrastructure. He lives with his wife, son and daughter.
Contents OVERVIEW OF SCHEDULE MANAGEMENT What is schedule management? Overview of the schedule management process Schedule and documents typically required for a project Schedule types in terms of presentation technique Schedule Management Techniques and Methods Critical Path Method (CPM) Earned Value Method (EVM) Program Evaluation and Review Technique (PERT) Rolling wave planning Applications for Schedule Management Primavera P6 MS Project MS Excel Primavera Risk Analysis Project Management Information System (PMIS) Organisations & Requirements for Schedule Management Schedule Management Team (Project Management Team) and other departments Is a scheduler a Primavera P6 operator? Contract type affects schedule management methodology Schedule levels and types Procedures Schedule-related standards Schedule management of portfolio and programme Schedule development process at the programme level Schedule structure in a multi-contractor project Preparing to develop a schedule Defining users and security profiles as well as layouts
Sharing layouts Settings in P6 Fifteen must-remember keyboard shortcuts in Primavera P6 Settings for a new project How do P6 users select duration types? How do P6 users choose Percent Complete Types? Columns and layouts Handy Tip – Finding missing activities Handy Tip – Customising names of timescale PLANNING & PUBLISHING Strategies in planning Requirement-oriented project management Schedule-related requirements in contract documents The dos and don’ts of developing a schedule Deceptive schedules are not allowed Requirements for counterparts Importing P3 files into P6 Data backup is the most important activity for P6 operators! Establishing a sandpit database Easy regular backup Handy Tip – Finding out who has changed a schedule in Primavera P6 Define scope and develop WBS Advance preparations Define scope and develop Work Breakdown Structure (WBS) Handy Tips – Various WBS development methods Organisation Breakdown Structure and responsibility assignment matrix Developing schedule management documents Develop activity list and sequences Recommendations for activity numbering and naming structure Ways to rename activity IDs
Creating an activity list (or draft of a schedule) and sequences under a work package Setting steps Handy Tip – Importing data from Excel to P6 WBS summary activities and level of effort (LOE) Using filters efficiently Loading resources Properties of resources Role, resource and work crew Developing a quick S-curve (Top-down resource allocation) Resource loading (Bottom-up resource allocation) Monitoring the progress of Physical (deliverables), Units (resources) and Duration Easy resource loading and project statusing Handy Tip – Erasing all units assigned to activities in one go Developing activity duration and relationships Duration units and activity duration estimation Graphical evaluation and review technique (GERT) for inspections and tests Schedule contingency Suspending and resuming an activity Activity relationships between work packages Negative value lag (lead) Handy Tip – Removing multiple relationships Assigning calendars Working hours per day Workable days per week Non-working days of the year Handy Tip – Viewing 12 months at once Assigning constraints and activity codes Assigning constraints Activity codes Comparing activity codes and UDFs (User Defined Fields) and global change
Handy Tip – An easy way to change the order of columns in an activities table Refining the schedule Check the basics Scheduling Schedule log review Finding missing relationships Spatial constraints review Intentional delay Levelling resources What-if scenarios Analysing the schedule Defining critical activities Critical path and near-critical path Handy Tip – Showing near-critical activities graphically Risks analysis Handy Tip – Finding lag Remaining early cost curve and payment curve Organising milestones Checklist before submitting schedule to client in the planning phase UPDATING, ANALYSING AND REPORTING Methodologies and processes of progress updating Data to maintain in the implementing phase Communication types for collecting progress data Collecting progress data by means of XER files Handy Tip – Importing a higher version XER file Collecting progress data by means of an Excel file Collecting progress data by means of a Project Management Information System Updating the schedule Prior to updating progress in Primavera P6 Progress updating for each type of activity
Summarising and storing period performance Handy Tip – Updating progress (EV) using Activity % complete Setting the Data date Technique for computing Performance percent complete Handy Tip – Computing the workload of schedule updating The reasons why Actual Cost should be updated Analysing progress Comparing schedules Earned Value Method Payment calculation Performance analysis Controlling the revision number of the master schedule Corrective actions and schedule revising Activity delay Delay by retaining logic Corrective actions for delayed activities Example of crashing based on Minimum Cost Expediting Process for revising the project schedule Reporting Effective progress report Developing reports with Primavera P6 Sample monthly progress report Printing Probability of on-time project completion Handy Tip – Displaying all activity names when printing out SCHEDULE-RELATED CLAIMS AND ADVANCED TECHNOLOGIES Delay analysis As-planned versus As-built Window analysis method Impacted As-planned
Time Impact Analysis Detail process of Time Impact Analysis Dispute resolution and FIDIC FIDIC Schedule-related conditions Issuing claims Dispute Adjudication Board (DAB) and the dispute resolution process Advanced technologies for schedule management 4D schedule management tool Schedule presenting methodologies – Line of balance XML format Recommendations for upgrading Primavera P6 PPM NAM – A new approach to analysing the project schedule Defining the priority of near-critical paths to monitor Monitoring near-critical paths Conclusion APPENICES Acronyms Calculation of data fields used in Primavera P6 References
OVERVIEW OF SCHEDULE MANAGEMENT
What is schedule management? The aim of schedule management is to complete a project within the timeframe set by a contract agreement or approved by a project owner. When it comes to contractors, time management is one of the biggest challenges because: •
Delivering projects on time is the top priority, as project claims often centre on schedule issues.
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Time is not procurable, except when contractors procure it by claiming an extension of time (EOT) for delays caused by the client.
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Time passes, no matter what; contractors cannot stop it like they can adjust costs and resources.
Schedulers are required to develop a project schedule that will be used not only for managing project time, but also for analysing risks and communicating with all project participants. Thus, many projects require schedulers to have abundant experience and knowledge of schedule management. To develop a reasonable project schedule and manage it efficiently, schedulers use schedule management methodologies (CPM, EVM, PERT, etc.) and software packages (Primavera P6, MS Project, MS Excel, Primavera Risk Analysis, etc.). When it comes to larger projects, it is almost impossible to manage all of the schedule data without software packages. Sometimes schedule management means utilising scheduling applications based on the schedule management theories and methodologies. Thanks to advanced technology, scheduling applications have become more sophisticated. Accordingly, schedulers have to deal with greater amounts of schedule data, and understand data flow to manage them. Above all, it is critical to understand the relations between data; schedulers are sometimes bewildered when they update their schedules only to find that the project progress does not show what they expected. Figure 1 shows the structure of progress data for cost in Primavera P6. If a scheduler understands this structure, he or she can easily find any data that have been input by mistake. Figure 1 – Structure of cost progress data in Primavera P6
OVERVIEW OF THE SCHEDULE MANAGEMENT PROCESS The schedule management process consists of two phases – planning and performing. The planning stage comprises defining, decomposing, assigning, scheduling, and analysing processes, as shown in Figure 2. Figure 2 – Planning phase
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A project starts with the signing of a contract by which quantities of deliverables, payment and project duration are set.
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Based on the contractual documents, the project’s objectives, scope of work and additional requirements are identified.
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To find any constraints (contractual dates and benchmarks) to be taken into account in developing a project schedule, schedulers should carefully review contractual terms and conditions, as these will be critical in issuing and resolving any project claims later.
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With the requirements and constraints found in the contract conditions, schedulers decompose deliverables by creating a Work Breakdown Structure (WBS) that will be the basis for communication between the client and the contractor. Components at the lowest level of WBS are called work packages, and they should be measurable and assignable for responsibility assignment, progress monitoring, project controlling, and communication between project participants.
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Organisation breakdown structure (OBS) will be developed based on the project type and size, and work packages are assigned to it.
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The work packages will be divided into tasks (activities) by schedulers or staff at departments and field sites, or by subcontractors, and activities will be linked with each other.
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Resources (personnel, equipment, or materials) and calendar are assigned to activities to compute proper durations.
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Appropriate activity codes will be assigned to the activities for easy grouping, filtering and sorting.
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To optimise a project’s master schedule, schedule engineers have to develop multiple scenarios to meet the schedule-related requirements suggested by the contract agreement, considering construction methods, resource and staffing plans, and the constraints of the workplace.
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Prior to being submitted to the project owner or client, the master schedule will be reviewed to assess schedule-related risks.
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After approval from the client or project owner, the master schedule will be issued to relevant organisations, departments, and project participants (e.g., subcontractors).
Since a project is a temporary endeavour undertaken to create a unique product or service, schedulers will experience an iterative planning process (decomposing, assigning, scheduling, and analysing) before the master schedule is approved by the client or project owner. As shown in Figure 3, the performing phase involves four processes – actualising, monitoring, analysing and revising (if necessary). In the performing phase: •
In accordance with the master schedule, departments, field site offices or subcontractors will perform activities to actualise deliverables; their performance, and completed and/or progressed deliverables, are monitored periodically.
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Based on the collected progress data, schedulers update the schedule and analyse the project status (scheduled dates and activity progress); the baseline and updated schedule will be compared to find any variances between planned duration and actual duration, and planned dates and as-built dates (start and finish). Figure 3 – Performing phase
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To evaluate performance with Earned Value Method (EVM) technique, resource productivity and cost usage are also monitored.
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When there is any delay in the project schedule, the impact of the delay will be analysed; if the delay has been caused by the client, the contractor will prepare documents to issue a claim for an EOT.
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If necessary, the project schedule will be revised; to revise the project schedule, a scheduler will incorporate approved change orders and prepare a recovery plan (fast-
tracking or crashing) with the help of counterparts at departments, field site offices, and subcontractors. •
During the preparation of a progress report, schedulers will perform additional tasks, including trends identification and forecasts development.
•
Then the progress report will be submitted to the client.
Figure 4 illustrates a summary of a typical process of schedule management in terms of transmitting data, information and reports between organisations. Figure 4 – Typical process of schedule management
SCHEDULE AND DOCUMENTS TYPICALLY REQUIRED FOR A PROJECT Below are the documents and information required by clients regarding schedule management: •
Schedule Management Plan – This provides outlines for the schedule management of a project. It generally consists of the schedule management approach, schedule control, schedule changes and thresholds, scope change, procedures for developing and changing the schedule and progress monitoring, and standards for creating and managing schedule data.
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Baselines – These are the aggregated values of planned progress over the project period. Theoretically, there are two types of baselines: schedule baseline and cost baseline. The schedule baseline is used as a basis for measuring the project progress, and the cost baseline is used for monitoring the monthly payment plan. These baseline values refer to the Planned Value (PV) in EVM. While applying EVM in progress monitoring, schedule baseline and cost baseline are not clearly separated.
•
Schedule (Master Schedule) – A schedule typically consists of activities, their dates
(start and finish), and a bar chart. From the perspective of a contractor, the master schedule and baselines are not separated; however, if client staff is not proficient with electronic scheduling files, the master schedule and baselines can be processed in different ways – the Master Schedule in P6 format and the baseline in Excel format, for example. •
Network Diagram – This shows the relationships between activities, and is used to judge the impact of predecessors’ delay. If a schedule is created using scheduling software, the network diagram is not necessary in deed; however, if the client staff is not proficient with electronic scheduling files, the diagram should be prepared.
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Analysis Report – When the master schedule or the project progress report is submitted to the client, analysis reports for the master schedule are attached. Analysis is typically performed on critical path and schedule-related risks. Critical path analysis focuses on finding the critical activities on the critical path which defines the project duration, as well as the near-critical activities which are not on the critical path but can become critical activities due to activity delay. Although it is very difficult to find schedule-related risks, schedulers can manage them with Primavera Risk Analysis, a software package developed by Oracle.
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Regular Progress Report – Progress reports are prepared and submitted to the client or project owner to apprise the project status. The progress report will contain physical progress (Earned Value), which will be the basis for identifying the actualised activities and delayed activities and calculating the payment amount. Clients usually require a monthly progress report and a quarterly progress report, and sometimes a weekly progress report.
SCHEDULE TYPES IN TERMS OF PRESENTATION TECHNIQUE As schedule management techniques and tools have been improved, many types of schedule presentation techniques have also been devised. A project schedule can be represented as follows: Figure 5 – Sample Gantt Chart
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Gantt Chart – A type of bar chart (see Figure 5), suggested by Karol Adamiechi in 1896 and independently developed by Henry Gantt in the 1910s, that illustrates the start and finish dates of activities in a project. The Gantt Chart shows no relationships between activities, thus it is difficult to check whether start and finish dates are correct in a mega-scale project; however, current scheduling software packages (Primavera P6, MS Project, etc.) adopt this schedule representation method assigning relationships to activities, resulting in automatic date calculation.
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Network Diagram – This currently uses Precedence Diagramming Method (PDM), also known as Activity on Node (AON), and was devised to help understand relationships between activities, as shown in Figure 6. Although scheduling software has a function to represent a network diagram, this method also has constraints in illustrating a large number of activities and their relationships. Thus, schedulers generally use this only when printing out a network diagram to identify the impact of an activity delay. Figure 6 – Sample Network Diagram
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Time-Distance Diagram – This is a schedule that has a Y-axis for time scale and an Xaxis for distance, as shown in Figure 7. It is apt for projects with long, narrow sites, such as railways and roadways. It consists of multiple graphic symbols. Once a user gets used to the symbols, it becomes easy to understand the whole project and project status. Figure 7 – Sample Time-Distance Diagram
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Computerised Database (or File) Schedule – Current schedule management software packages, such as Primavera P6, MS Project, Primavera Risk Analysis and Tilos, use a database or file with schedule data used for calculating the start and finish dates of activities, and graphical representations such as a Gantt Chart, Network Diagram, or Time-Distance Diagram. Schedule management software packages also allow users to load resources on activities so that schedulers can manage resources. Figure 8 is a screenshot of an activity usage profile in Primavera P6 that shows the budgeted cost of a project, which the financing team can use to develop a financing plan or ask the project team to make changes to the project schedule in order to meet the S-curve, for example. The horizontal red line on the lower left indicates funding constraints. Since a schedule generally has graphic elements, people tend to accept only schedules that are illustrated graphically; however, for performing tasks correctly and resolving claims in a dispute, schedule data (start and finish dates, predecessors and successors, lag and lead, etc.) and progress data (remaining duration, per cent of completion, actual units, etc.) are more critical than bar chart schedules, diagram schedules, etc. Schedule and progress data are created with the help of a computerised schedule. Figure 8 – Activity usage profile
Schedule Management Techniques and Methods Since all schedule-related software packages, contract conditions, and processes and procedures are based on schedule management techniques and methods, schedulers need to understand them well.
CRITICAL PATH METHOD (CPM) Generally speaking, the contract scheduling specifications mandate the use of critical path method (CPM) in developing schedules for construction projects. An understanding of the underlying mathematics that form the basis of critical path methodology is a necessary prerequisite to understanding schedule management and its requisite skills. CPM is a project planning and scheduling technique to calculate the float of each activity with forward pass method (FPM) and backward pass method (BPM), revealing the critical path on which the critical activities lie. The critical path is the longest sequence of activities in a project schedule (which refers not to the number of activities on a path, but to their total duration). This defines the duration of the project. Below is a network schedule (see Figure 9) for an overseas business trip, illustrating how to define critical activities and calculate early start and finish dates, late start and finish dates, and the float of each activity using CPM. Blue boxes show various activities, and each has a letter and a number corresponding to the activity name and duration, in days. According to the schedule, preparation for the business trip begins with getting permission for the trip (Activity A) and has three paths – buying a bag, renewing the passport, and booking airs. The traveller has three paths by which to prepare his journey prior to taking the trip (Activity G). Figure 9 – Schedule for an overseas business trip
Even if he has completed booking (E) and reserving (F) early, he cannot start his journey because the passport has not been renewed yet – a process that takes 11 days to complete. As a result, the critical path of the schedule is A-D-G and the total duration of the path is 17 days, meaning that the project will take 17 days to complete from the beginning (A) to the end (G). What if the duration for renewing his passport decreases to five days? In that case, the
critical path will change from A-D-G to A-E-F-G, and require a total of 13 days. What if activity B is delayed 10 days, taking 13 days in total, while activity D takes 11 days? In this case, the path A-B-C-G will become the critical path. As such, duration changes can change the critical path, which depends on each activity’s float. Float, also known as slack, is the amount of time that an activity can be delayed without causing a delay of the project completion. The float that does not delay project completion is called total float, and the float that does not cause a delay of subsequent tasks (successor activities) and project completion is called free float. The float of each activity can be computed by FPM and BPM. Figure 10 – Forward pass method
FPM is used to estimate early start and finish dates for each activity. The red numbers above the boxes in Figure 10 indicate the early start and finish dates of each activity. Activities B, D and E can begin on day 2 after Activity A is complete, Activity B will be finished on day 4, and then Activity C can start on day 5. Activity G can begin after all of the preceding activities (C, D and F) are completed. Figure 11 – Forward pass with SS relationship
When the relationships are start-to-start (SS), the early start date of the successor activity always depends on that of its predecessor(s). Figure 11 shows an example of FPM, where activities A and B have FS (Finish-to-start) relationship and activities B and C have SS relationship. Even though Activity A finishes on 7 May, Activity B may need to start on 12 May due to a lag between activities A and B, or calendar setting including nonworkable days, for example. Consequently, Activity C can start on 12 May because its predecessor (Activity B) starts on 12 May. BPM is the opposite of FPM in that it computes the dates by calculating from the final activity (Activity G). The blue numbers below the boxes in Figure 12 are the late start and finish dates. Activities C, D and F can be completed on day 12, before Activity G begins, and Activity C can start on day 11 because it requires two days.
Figure 12 – Backward pass method
For finish-to-finish (FF) relationships in BPM, calculation is slightly different. If there are no successors, the late dates depend on the date of the final activity. Figure 13 shows an example of BPM, where activities A and B have FS relationship and activities B and C have FF relationship. Since Activity C has no successors, the late finish date depends on that of Activity A. Figure 13 – Backward pass with FF relationship
The difference between early start and late start (or early finish and late finish) is called “total float”. As mentioned earlier, total float is the float time within which an activity can be delayed without affecting the completion date of a project. In Figure 12, the total float of Activity C is 6 days, which means that Activity C can be delayed 6 days without causing a delay in project completion. On the other hand, Activity D has no float, which means that if Activity D is delayed, the completion of the project will also be delayed. Generally, the sequence of activities with zero float is considered the critical path, and the activities on it are called the critical activities or critical path activities. Thus, the critical path on the schedule is A-D-G. In a working schedule that has a calendar set with non-workable days and a lot of activities with complicated relationships and constraints, a critical activity can have any number other than zero (0), so Primavera P6 provides two options to find the critical path – “Total Float less than or equal to 0 (days)” and “Longest Path”. When you choose Longest Path, you will find more realistic critical activities. On the other hand, what if activity F is delayed 7 days? The critical path will be changed from A-D-G to A-E-F-G, as shown in Figure 14. In a project, the critical path changes frequently. Therefore, schedulers should continuously monitor and manage any paths that could become the critical path. The path that has the greatest likelihood to become the
critical path is called the near-critical path, and the activity on the near-critical path is called the near-critical activity. They all are defined based on the amount of the total float. Figure 14 – Changed critical path
EARNED VALUE METHOD (EVM) EVM, also known as earned value management, is a project management technique to measure project performance, progress and cost in an objective manner. What is value in EVM? An activity’s value can be calculated from its assigned resources or, if there is no resource assigned, a weight factor based on its relative importance compared with other activities. Figure 15 shows how to calculate value for each activity – the upper table is based on resources and its quantities and unit price, and the lower table is based on weight. Value in EVM is presented as money or cost. Figure 15 – Calculating values
In Primavera P6, weight factor is used to assign value to the Steps of an activity. For instance, if a contract has been made to produce 20 newly designed chairs at 2,000 USD, each chair can be 100 USD (5%) in terms of value; however, all products are usually delivered in a lump after going through designing, manufacturing and testing, so the value (cost) should be restructured as: designing 200 USD (10%), manufacturing 1,200 USD (60%), testing 400 USD (20%), and delivering 200 USD (10%). Since there is no standard for defining Steps, schedulers should discuss and define Steps with the client prior to developing the schedule.
EVM requires three basic values: •
Planned Value (PV) – PV can be defined as scheduled progress. When developing a schedule, a scheduler assigns resources (or a weight factor based on cost) to each activity. After scheduling, an activity will have start and finish dates as well as value over the activity duration; this is called PV or planned progress.
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Earned Value (EV) – EV is measured progress for a product on the basis of the predefined value of deliverables.
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Actual Cost (AC) – AC is the cost incurred for the actual tasks completed.
In Primavera P6, PV has slightly different definitions. PV is the planned value based on the data date (DD). The DD is the progress point or as-of date used as the basis for calculating project progress and remaining durations. You can set the DD when you schedule the project. PV and EV have different names in Primavera P6 – Planned value cost and Earned value cost, respectively. Figure 16 – Example of computing PV and EV
Figure 16 shows an example of computing PV and EV in Primavera P6. The Budget at completion (BAC) of an activity is the planned (baseline) cost through its completion and the Schedule % complete specifies how much of the activity’s project baseline duration is complete as of the project DD. Figure 17 shows how to calculate the Schedule % complete of an activity. The yellow bar shows the baseline duration, the blue bar is the actual (progressed) duration, the red bar shows the remaining duration to complete the activity, and the red vertical dashed line is the DD. As of the DD, the Schedule % complete is calculated as “a” (progressed baseline duration) divided by “b” (the total baseline duration). PV is calculated as BAC multiplied by Schedule % complete. The Performance % complete of an activity is the percentage of its performed work as of the DD. EV is calculated as BAC multiplied by Performance % complete. And AC is the actual total cost (labour costs plus non-labour costs plus actual material costs plus expense costs) incurred leading up to the DD. Figure 17 – Computing Schedule % complete of an activity
To conclude, below are processes through which to use EVM to monitor and analyse the progress and performance of a project: •
The scope of a project is decomposed into numerous tasks and value (budget, resources, or weight factor) for each task is defined and assigned to each task.
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A project baseline (or Planned Value) is established through scheduling.
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Then the project progress is measured as of the DD in terms of EVM – PV (work planned to be completed), EV (work actually completed), and AC (cost incurred for work completed).
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SV (Schedule variance) and SPI (Schedule performance index), CV (Cost variance) and CPI (Cost performance index), Estimate to complete (ETC) and Estimate at completion (EAC) and others are computed based on these three values (PV, EV and AC).
PROGRAM EVALUATION AND REVIEW TECHNIQUE (PERT) PERT was devised to analyse projects that have a lot of uncertainties in scheduling, and to help reduce risks in schedule management. Based on PERT, the average duration of each activity will be computed as shown in the equation below.
With the optimistic duration and the pessimistic duration, standard deviation for each activity can be calculated as shown in the following equation:
Based on average duration and standard deviation, each activity has a Z-score, also known as a standard score, for target duration as shown in the equation below:
With a Z-score and Standard statistical table (See Figure 18), schedulers can calculate the probabilities of target durations for each activity. According to the Standard statistical table, if a Z-score for a certain activity is 0.34 for a target duration, the probability is 63.31%. This means that the activity has a 63.31 % chance of completion for the target duration. Figure 18 – Standard statistical table for Z-score
The current version of Primavera P6 does not provide a feature to utilise PERT in calculating activity durations or project duration, while Primavera Risk Analysis, a software package for schedule analysis, does. Primavera Risk Analysis estimates a project duration using Monte Carlo Simulation, suggesting probabilities of project completion for various project duration scenarios. For instance, it shows that the probabilities that a project is completed on time, a month early or a month late will be 47%, 5%, and 78%, respectively; however, when applying PERT, schedulers should take into account that: •
It is not easy to judge the optimistic duration and the pessimistic duration for each activity; they vary due to working conditions.
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Indeed, duration can be shortened easily by recovery methods such as crashing and fast-tracking.
ROLLING WAVE PLANNING Rolling wave planning is a method of scheduling by which tasks to be done in the near term are planned for a higher summary level. Near-term in construction projects typically implies several months from the current date, and this technique is frequently used in mega-sized construction projects with long durations. When a project begins, a contractor is required to develop a master plan which covers all components of the project within two or three months. Within such a short duration, it is not possible to develop a reasonable and robust master schedule that includes all tasks fully detailed enough to carry out. Thus, the master schedule will first be created as a summary level schedule. Each month, the contractor will develop the detailed rolling schedule in which all near-term (e.g., three or four months) tasks are planned to a lower, discrete level of detail. Activities at a lower level of detail in the rolling schedule include
those that can help schedulers identify project problems, conflicts, and risks. The rolling wave method is frequently used in gigantic construction projects, as well as long-term development projects, because it helps schedulers: •
Have time to review contractual conditions which should be included in the project schedule as detailed activities.
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Have enough time to take into account on-site situations relevant to staffing, procuring resources, etc.
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Minimise low-level schedule changes.
Applications for Schedule Management Schedulers deal with many activities every day. Even a small mistake in processing schedule data can affect the entire project schedule. Thus, schedulers should try to manipulate schedule data not manually but systematically, or automatically, if possible. The software packages and add-ins introduced here are used world-wide for schedule management; they help schedulers deal with schedule data rapidly and prevent them from making mistakes.
PRIMAVERA P6 P6 is one of the most powerful schedule management tools. As it has a lot of features that require various data types, its data structure is very complicated, so users need to understand the structure before using it. There are two types of Primavera P6 products – P6 PPM (Professional Project Management) and P6 EPPM (Enterprise Portfolio Project Management). P6 EPPM is a web-based application more focused on the enterprise as a whole – strong portfolio management, enterprise dashboards, a future project selection tool, etc. On the other hand, P6 PPM is used as a standalone application accessing a locally installed database, such as Oracle XE or Microsoft SQL Server. It provides a multi-user system if database server can be shared. The usages and tips in this book will be mainly for Primavera P6 PPM. Primavera P6 PPM (Release 15.1) has eight menu groups, which have commends to operate P6, twelve windows, ten dictionaries and lots of dialogue boxes to control data (see Figure 19). Figure 19 – Screenshot of Primavera P6 PPM (version 15.1)
As various schedule data is manipulated in the windows, users need to know the function of each window. •
Projects – Used to view the Enterprise Project Structure (EPS), and to navigate to specific projects. It provides the programme-level overview of all the schedules that
exist in the Primavera P6 database. •
WBS – Used to view, create, and manage the database’s various work breakdown structures.
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Activities – Used to view, create, and modify activities in an open schedule. This window is used the most, and provides six views: activity details, activity usage spreadsheet, activity usage profile, resource usage spreadsheet, resource usage profile, and activity logic.
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Resources – Used to view, create and manage resource items at a global level. Properties of resources can be manipulated in this window.
•
Reports – Provides access to the preformatted, text and graphical reports, and to the report-writing functions.
•
Tracking –Used to display and create tracking layouts for the open project.
•
Resource assignments – Used to view, add, and delete resources assigned to activities. This window provides a similar view with activity usage spreadsheet of Activities window.
•
WPs & Docs – Used to create and assign work products (WPs) and documents (Docs) for an open project.
•
Project expenses – Used to manage indirect costs and expenses for a project.
•
Risks – Used to add, delete, or calculate risks and their impacts for an open project. The overall risk score varies from 0 to 72 based on the values of three fields: probability, cost, and schedule. Cost and schedule fields are the impact fields; whichever is higher is used to compute the score.
•
Project thresholds – Used to add or delete thresholds for an open project. A threshold is a variance range on a given parameter, such as start date variance, which can be applied to a specific work breakdown structure element. Thresholds can be used to monitor performance.
•
Project issues – Used to add, delete, or modify issues for an open project. Issue files are useful for tracking the ongoing history of a specific activity.
Dictionaries in Primavera P6 PPM have codes and settings to be assigned to projects or activities. P6 operators can manage codes and settings in the dictionaries, and dictionaries for calendars, activity step templates, activity codes, user defined fields are commonly used. If you want to view the dictionaries toolbar, you can select it in Toolbars from the View menu. Figure 20 illustrates the hierarchy used in Primavera P6. New projects can be created in the lowest levels of EPS; these levels will contain different versions (or copies) of the project. Each project will have a WBS, and its lowest level will be a work package. Under
each work package, activities will be created (some activities have Steps). Figure 20 – Hierarchy in Primavera P6
MS PROJECT MS Project (see Figure 21) is a schedule management software package with an interface similar to MS Excel, so any user who is familiar with Excel may easily learn how to use it. Figure 21 – Screenshot of MS Project
It performs almost all the functions Primavera P6 PPM does, with the following exceptions: •
MS Project changes activity numbers automatically when inserting or deleting an activity, as shown in Figure 22. The original activity numbers of “Construction Plan” was 48 but it has been changed to 49 due to an inserted activity (New Task).
•
MS Project does not allow multiple users to work on a single project at the same time because it does not operate based on a database. Recently, MS Project has been upgraded with database functions.
•
In MS Project, there is no need to separate WBS or activities. Any element at the lowest level becomes an activity, and accordingly any entity (activity) with child activities becomes WBS.
•
MS Project does not have a feature to create Steps for an activity.
Figure 22 – Revised activity numbers due to an inserted activity
MS Project is currently used in many projects, so Primavera P6 users will probably experience using MS Project schedule files from time to time. Indeed, it is impossible to import files (.mpp) directly from MS Project version 2013 into Primavera P6 version 15.1. According to Figure 23, XML and XLS formats are the only ones that Primavera P6 and MS Project users can share; however, XLS formats have limitations in transferring schedule data, so users mainly use XML. Figure 23 – Exportable and importable format
To import an MS Project file into Primavera P6: •
In MS Project, save a schedule with extension “XML”.
•
With Primavera P6 open, go to the File menu and click Import.
•
When the Import dialogue box appears, choose “Microsoft Project”, select XML, and then click Next.
•
Choose the XML file that you have saved and click Next.
•
In the next dialogue box, add a new template and click Next.
•
If you click Finish, you will see Primavera P6 start transforming automatically.
•
Click Close and review the imported schedule to confirm that it looks correct.
MS EXCEL Put plainly, Excel does not have any features for schedule management; however, it can
play a significant role in schedule management. Although Primavera P6 provides functions that help schedulers review and analyse schedule and progress data, the features in the application are limited, while Excel allows users to manipulate data in unlimited ways. Furthermore, lots of mini applications (with wonderful features), such as XER File Parser and P6XL Bridge, exist as add-ins in Excel. MS Excel supports the following features: •
Manipulating and importing data – It is much easier to create and manipulate schedule data in Excel than in P6. Most P6 users use Excel to prepare schedule data and P6 to schedule it.
•
Dashboard – P6 has rudimentary graphic reports. Once you created a dashboard with graphics in Excel, all you need to do is copy data in P6 and paste it in Excel.
•
Developing cost curves – With Remaining early cost and Remaining late cost, schedulers can create early cost curves and payment curves in various ways in Excel.
PRIMAVERA RISK ANALYSIS Primavera Risk Analysis, developed by Oracle, is useful to analyse and find schedulerelated risks in a project schedule, using Monte Carlo simulation for the optimistic duration, most likely duration, and pessimistic duration of each activity. People use Primavera Risk Analysis (PRA) because: •
It has features to define the probability of success for a project in terms of schedule (see Figure 24). Figure 24 – The probabilities of success
•
It helps identify high risk areas in the project schedule and project management to focus key resources where attention is needed.
•
It helps schedulers prepare a reasonable mitigation plan on the basis of quantitatively identified risks.
•
It provides on-going risk management strategies by reviewing schedule risks in the implementing phase.
The mitigation plan and the risk management plan that you have prepared on the basis of risk analysis may help assure your client that you are looking ahead and prepared for any potential impacts. Tilos Tilos is time-location chain scheduling tool showing the status and progress of deliverables graphically over the project period. It is useful for construction projects which have narrow and long field sites such as railways and roadways. One of the advantages of using Tilos is that it can illustrate a graphical schedule (see Figure 25), which allows schedulers to view the whole project schedule easily and identify any schedule-related interferences between disciplines. Figure 25 – Time-Distance Chain Schedule
Small applications The following utilities help P6 users communicate with the P6 database or manipulate schedule data (they are available on websites and some are free): •
XER File Parser – An Excel file provided by Oracle that can read the data contained in a “.xer” file, and gives the users the ability to modify information and build a new XER file to import to Primavera P6.
•
P6XL Bridge – An Excel file using the P6 SDK (Software Development Kit) to help users communicate with P6 SQL database.
•
XER Reader – An Excel Macro file to run DCMA (The USA Defense Contract Management Agency) 14 point checks. The DCMA 14 Point Metrics were developed to identify potential problem areas with a contractor’s master schedule.
•
ASAP Utilities – An Excel add-in that fills the gaps in Excel. When manipulating
schedule data in Excel, it provides users with very convenient functions. •
Change Inspector – This helps users find updates in P6 XER files, such as activities added or deleted, dates changed, changes to calendars, etc., by comparing the updated XER file and original XER file.
•
XER Manager – This helps users see the details of XER files and clean them by deleting unnecessary data prior to sending to others and/or importing it.
•
XER Toolkit – An Excel add-in that provides a lot of features for XER analysis, such as statistic of activities, relationships, etc.
If you can use the SDK (Software Development Kit) which is an optional component of Primavera P6, you will save time because it makes the P6 database available to external applications.
PROJECT MANAGEMENT INFORMATION SYSTEM (PMIS) Although schedule development is performed by the schedule management team (or schedulers), progress monitoring requires supports from departments or field site offices. On some mega-scale projects, the Project Management Information System (PMIS, also called Progress Management System) is designed for defining Physical (deliverables in P6) or Steps, helping staff in field site offices input progress data and descriptions of delay, and illustrating summarised progress for the client. Figure 26 – Screenshot of PMIS (SAP)
In the case of the Korea High Speed Rail project, a progress management system called KPROMIS was developed around 1998. KPROMIS was a client-server-based system used in the first section of the line. In 2005 it was converted into a web-based system for the second section of the line. The database architecture of KPROMIS was designed to be somewhat simple in order to help schedulers manipulate the database with ease, but it still provided powerful features. After establishing or revising the project master schedule, schedule data for progress monitoring is entered into the system as a planned schedule, which includes the activity
number, activity name, WBS number, WBS name, start and finish dates, and activity owner name. At the end of every month, activity owners (counterparts at departments or field site offices) input progress data, which includes actual start or finish dates, per cent of completion, expected start or finish dates, and reasons for delayed activities and their recovery plans. Any activity below 85% of performance compared to planned progress (Physical or Steps) or the activities that have not started or finished on time are identified as delayed activities. After activity owners complete the updates, schedulers summarise the project progress and analyse the project status based on the progress data in the system.
Organisations & Requirements for Schedule Management Note that this book frequently explains the concepts and theories of schedule management from the perspective of a scheduler of a big construction project as if he or she has numerous field site offices and subcontractors to control at the same time. This standpoint has been selected because it covers all aspects of schedule management – the jobs of Primavera P6 operators, schedule and progress data collectors, and schedule managers.
SCHEDULE MANAGEMENT TEAM (PROJECT MANAGEMENT TEAM) AND OTHER DEPARTMENTS On a big project, the schedule management team generally consists of a planner (or planning engineer), a lead scheduler, and P6 (or MS Project) operators. The planner is responsible for defining the work scope of the project and developing WBS identifying work packages, as well as preparing the progress reports. The lead scheduler and P6 operators work on scheduling, progress monitoring, and schedule updating and controlling. The schedule management team cannot manage the project schedule alone. From the beginning of schedule development to the end of the project, the schedule management team needs the help of departments, field site offices and subcontractors. Thus, the member of the schedule management team should frequently communicate with a Project Manager and staff of other departments and field site offices to lead project schedule smoothly. Here are some strategies for building your schedule management team and developing good relationships with other teams: •
Share all information with your team members, as well as their counterparts, including departments, field site offices and subcontractors.
•
Secure as many communication channels with your counterparts as you can and maintain them. The key to schedule management is to communicate effectively with your counterparts.
•
Eliminate unnecessary steps or processes in cooperating with other teams.
•
Record all events related to schedule management, such as submission and approval of schedule, etc. The records will be useful in issuing claims or resolving disputes.
•
If possible, produce electronic files instead of paper-based documents. MS Word, Excel or any other software will help you process electronic files automatically and systematically all at once, saving time and preventing mistakes. Furthermore, the
electronic files can easily be shared with others. •
Remember that any repetitive manual work can be processed automatically without your effort. By leaving it to the computer, you or your team members can save time and focus on more productive work.
•
Do not be afraid to ask your counterparts for help, no matter what kinds of problems arise (including those related to Primavera P6). No one knows everything.
IS A SCHEDULER A PRIMAVERA P6 OPERATOR? Schedulers are not just Primavera P6 operators. They should have the ability to depict an entire project processes (see Figure 27) and control all the activities at the same time because activities in a project have very close relations with each other, affected by their predecessors and affecting their successors. A project schedule will be loaded with resources, and all the risks and issues will be identified there. A scheduler sometimes needs to take the role of a coordinator between counterparts at departments, subcontractors, etc. Consequently, schedulers should focus on all areas of a project, not just time management. Figure 27 – Example of the process of a railway project
Since clients now require more elaborate schedules than they used to, schedulers must have diverse skills and experiences. Below are the proficiency levels schedulers should have in using applications (1 is high and 5 is low): •
Primavera P6 (or MS Project) – 1
•
MS Excel – 2
•
PMS (or PMIS) schema – 2
•
Primavera Risk Analysis (or Pertmaster) – 2
•
Word and PowerPoint – 3
•
Tilos (for the schedulers of railway or roadway projects) – 3
•
CAD (Computer Aided Drawing) software package – 4
CONTRACT TYPE METHODOLOGY
AFFECTS
SCHEDULE
MANAGEMENT
Since schedule management methodology has a close relationship with payment type for the contract deposit, schedulers should take the type of contract into account. Contract types can be categorised as follows: •
Fixed-Price Contracts (FPC): The FPC type is commonly used in the construction industry and provides for a firm price or, in appropriate cases, an adjustable price. This type includes Firm-Fixed-Price Contracts, FPCs with Economic Price Adjustment, Fixed-Price Incentive Contracts (ICs), FPCs with Prospective Price Redetermination, and Fixed-Ceiling-Price Contracts with Retroactive Price Redetermination. Under FPC, Percent Complete Type of activities in P6 should be “Physical”.
•
Cost-Reimbursement Contracts (CRC): The CRC type provides for payment of allowable incurred costs, to the extent prescribed in the contract. This type includes Cost Contracts, Cost-Sharing Contracts, Cost-Plus-Incentive-Fee Contracts, Cost-PlusAward-Fee Contracts, and Cost-Plus-Fixed-Fee Contracts. Based on CRC, Percent Complete Type of activities in P6 should be “Units”.
•
Incentive Contracts (IC): The IC type is appropriate when the required supplies or services can be procured at lower costs and, in certain instances, with improved delivery or performance. Under the IC type, some activities will have “Physical” and others will have “Units” for Percent Complete Type, according to task type.
•
Indefinite-Delivery Contracts (IDC): The IDC type is a contract that does not specify a firm quantity of supplies or services and provides for the insurance of order for the delivery of supplies or the performance of tasks during the period of the contract. This type includes Definite-Quantity Contracts, Requirements Contracts, and IndefiniteQuantity Contracts. Under IDC, some activities will have “Physical” and others will have “Units” for Percent Complete Type, according to task type.
•
Time-and-Materials Contracts (TMC): The TMC type is used only when it is impossible to estimate accurately the extent or duration of the work. Based on TMC, some activities will have “Duration” and others will have “Units” for Percent Complete Type, according to task type.
•
Labour-Hour Contracts (LHC): The LHC type is a variation of the TMC, differing only in that materials are not supplied by the contractor. Under LHC, Percent Complete Type should be “Duration”.
SCHEDULE LEVELS AND TYPES
There are three types of schedule levels for different level of reviewers as follows: •
Level 3 Schedule – A master schedule used by schedulers and the staff of the departments of a contractor. It will be basis for all measurements, analyses, and calculations for the project progress and status. The number of activities depends on the size and characteristics of the project.
•
Level 2 Schedule – Summary schedule of Level 3 schedule. It is used by the staff of the client. The number of activities is approximately 300 to 500.
•
Level 1 Schedule – Summary schedule of Level 2 schedule. It is reported to the client’s management. To help management understand the whole process of the project, graphical elements (photos and symbols) or time-distance diagrams can be used in creating the schedule. The number of activities is approximately 30 to 50.
There may be three types of schedules submitted to the client for review, according to the contract: •
The Initial Schedule – A schedule to be submitted at the beginning of a project with a four- or six-month detail schedule.
•
The Master Schedule – A schedule to be submitted after submitting the Initial Schedule.
•
The Detailed Rolling Schedule – A schedule covering a two- or three-month detail schedule. To print a three-month detail schedule, any activities in progress and the activities that will start or finish within three months can be filtered, as shown in Figure 28. Figure 28 – Filtering activities
PROCEDURES In case of construction projects that involve many participants and various organisations
that have numerous contracts to control, and the role of Project Management Consultancy (PMC) is to coordinate schedules, it is essential to prepare procedures for good communication in schedule management. Generally, three types of procedures for schedule management are shared among the project management team and department, subcontractors, and the client – schedule development, progress management, and schedule change. Figure 29 – Schedule development process
Figure 29 illustrates a schedule development process for a construction project with multiple contractors. Each coloured area shows the job area to be performed by the Client, PMC, Supervisor, and Construction Contractors. The rectangles show the tasks for each team, the arrows demonstrate the flow of information or deliverables, and the blue big rectangle shows the work scope of the schedule development. Since the project has multiple contractors, PMC should prepare an Integrated Project Schedule (IPS), a Level 2 Schedule, in order to integrate with the contractors’ schedules. With the IPS, contractors will develop their own Contractor Working Schedules (CWS), a Level 3 Schedule, to be reviewed by a supervisor. If there is only one contractor in the project, it is not necessary to prepare the IPS prior to CWS. Instead, CWS serves as the basis for the IPS. A Milestone Summary Schedule (MSS) is a Level 1 Schedule. Figure 30 – Progress management process
Figure 30 shows a sample progress measurement process in which the coordination meeting (or a monthly meeting) may be held to review project progress and discuss critical issues. After executing the tasks, the contractor will input progress data into the system or update their schedule, and then the supervisor will review the project progress. If there are any issues related to EOT or changes to the master schedule due to delayed activities, the contractor will issue a letter to require the EOT and/or prepare a schedule change proposal. The supervisor will review the schedule change proposal and decide to accept or deny it. If the supervisor denies it, the contractor should prepare a recovery plan for delayed activities and their successors to meet the project duration approved by the client. In the meeting, the client and PMC will review the preliminary monthly progress report, including the schedule change proposal, if applicable. Figure 31 – Schedule Change process
Figure 31 shows an example of the schedule change process. Schedule changes can arise due to delayed activities or various requests from the client. On projects that have multiple contractors, the IPS should be changed before any of the contractors’ schedules is changed, in order to best integrate all schedules. All changes to CWS should be reviewed by the supervisor, who should confirm that CWS have been revised based on the IPS.
SCHEDULE-RELATED STANDARDS For easy schedule management, a project team needs to prepare schedule-related standards
or criteria that will be shared with counterparts at departments, field site offices, and subcontractors. Details will be introduced in later chapters. •
Structure for schedule levels
•
Structure for schedule revision number
•
Structure for WBS IDs and names
•
Structure for activity IDs and names
•
Creating and erasing activities
•
Activity duration, relationships and constraints
•
Setting calendars
•
Baseline maintenance
Schedule management of portfolio and programme PMI (2013) suggests a hierarchy of strategic plans, portfolios, programmes, projects and sub-projects, as shown in Figure 32. Each level of the hierarchy is a collection of its lower levels. Portfolios or programmes do not need to be interdependent or directly related to each other, while projects and sub-projects are essential elements of their higher levels, and have close relationships with other elements at the same level. Figure 32 – Hierarchy of portfolios, programmes and projects
The role of managers for schedule management at each level is different. Project managers or sub-project managers have full responsibility for their projects or sub-projects schedule, and they try to trade off between time and cost to complete their tasks on time and within the budget. On the other hand, portfolio managers and programme managers are only interested in the necessity and the completion dates of their programmes and projects. While the responsibilities of project managers and sub-project managers begin after a project charter is issued or a contract is made, that of portfolio managers and programme managers begins before a project is created and mainly focuses on study to decide whether to begin a programme or a project. Thus, schedulers at the programme level have a different approach towards schedule management.
SCHEDULE DEVELOPMENT PROCESS AT THE PROGRAMME LEVEL Mega-scale infrastructure construction projects, such as housing complex development and conventional railway construction, consist of numerous sections and require various disciplines. Such projects should be redefined as programmes because they involve multiple contractors that can be defined as a project. Figure 33 illustrates the approach to developing the programme master schedule, which is a collection of the project schedules. First, the programme management team prepares a draft programme schedule that is created with assumptions such as approximate project scope, budget and schedule. Next, each project team develops its own schedule based on
the draft schedule. When developing a project schedule, the activities that need to be linked with other activities in other projects have to be documented. After collecting schedules from the project teams, the programme management team will put them together into a master schedule template and connect activities as per the documented relationships prepared by the project teams. If the draft master schedule does not meet the programme duration, the programme management team will communicate with project teams to adjust the schedules. When schedule adjustment is complete, a new master programme schedule will be published. With the master programmed schedule, each project team will develop its detail master schedules. Figure 33 – Programme schedule development process
SCHEDULE STRUCTURE IN A MULTI-CONTRACTOR PROJECT As mentioned above, coordinating schedules between projects is one of the biggest issues for schedulers of a programme management team in a multi-contractor project or multidisciplinary programme. Thus, they need to set a hierarchy of schedules as follows: •
MSS – MSS is the highest level of schedule to manage a programme or a multicontract project. It is created based on the IPS and includes only the major milestones of projects.
•
IPS – IPS is the second level of schedule used by schedulers of a programme management team.
•
CWS – CWS the lowest level of schedule developed by contractors based on the IPS and will be a part of contractual documents.
Preparing to develop a schedule There are lots of settings and options in Primavera P6. Each setting and option affects the schedule; thus, prior to developing the schedule, schedulers need to understand the options and settings in order to develop an appropriate schedule and manage it with ease.
DEFINING USERS AND SECURITY PROFILES AS WELL AS LAYOUTS Prior to planning, the users who will operate Primavera P6, as well as its security profiles, should be defined. If the P6 database is shared among P6 users on a big project, users can be classified as follows: •
P6 users of the schedule management team – They should have all privileges to access and control the database.
•
Counterparts at departments, field site offices, and subcontractors – They should have privileges to update the progress of their own activities only.
•
Counterparts at the client – They should have privileges to view P6 data only.
Primavera P6 provides features to configure screen layouts and save those settings for reuse. Schedulers, clients and staff in field site offices should prepare different layouts that allow P6 users at different levels to set layouts according to their use of P6. The client will use P6 to view the project schedule and progress, while staff in field site offices will use it to input progress data. To develop the layout for each counterpart, filter, columns, and bottom view should be set, which helps narrow down the data to be viewed in P6. For counterparts at departments, field site offices, and subcontractors: •
Filter – To filter the activities which belong to a certain counterpart, you have to create Activity codes for the responsibilities for each counterpart, assign them to activities, and then use Filter function to narrow down activities to view.
•
Columns – Columns in the activities table should include Activity ID, Activity Name, Original duration, Start, Finish, Performance % complete, Variance-BL project duration, Variance-BL project start date, and Variance-BL project finish date.
•
Bottom view – Activity details should have Status, Relationships, Resources, Steps, Expenses, Notebook, Risks, and WPs & Docs.
For counterparts at the client: •
Filter – Filter setting should be “All Activities”.
•
Columns – Columns in the activities table should include Activity ID, Activity name, Original duration, Start, Finish, At completion duration, Performance % complete, Planned value cost, Earned value cost, AC, Schedule variance, and Schedule
performance index. •
Bottom view – The Activity usage profile should be displayed. You have to customise the shape of the Activity usage profile for the client.
SHARING LAYOUTS Sharing layouts with other P6 users is easy. Follow the steps below to share your layout files: •
Set the current view by adjusting filter, activity columns, and bottom view, and then save the current view by selecting “Save layout as” in the View menu.
•
Open the layouts dialogue box by clicking “Open of Layouts” in the View menu. When you get a pop-up asking you to save changes to the current layout, select No if you do not want to save it.
•
Select the layout to export and hit the Export button in the dialogue box.
•
Choose what to name the file and where to save it. You will see the file you have just saved with extension “.plf”.
•
Now you can email that file to your colleagues.
Recipients can import the file into their Primavera database as follows: •
Save the “.plf” file that you have received to your computer.
•
Open the layouts dialogue box by selecting “Open of Layouts” in the View menu. When you get a pop-up asking you to save changes to the current layout, select No if you do not want to save it.
•
Hit Import in the dialogue box, and select the saved file.
•
Name the layout and save it.
•
Choose the layout in the Open layout dialogue box and hit the Open button to use it.
SETTINGS IN P6 Primavera P6 provides schedule engineers with multiple options to help them organise and manage project activities properly. When setting options in Primavera P6, users should take into account the contract type and the current project phase. P6 users can set the following options: Admin Preferences (Admin menu) •
Time Periods – All durations in P6 are stored as hourly-based data. “Hours/Day” in the option “Hours per Time Period” is for specifying the number of work hours for a given day. If “Hours/Day” is eight, five to twelve hours will be shown as one day due to rounding. Accordingly, 13 to 20 hours will be two days.
•
Earned Value – Users should specify methods for computing performance percent complete, Estimate to Complete (ETC), and the Earned Value from a baseline use.
•
Industry – This option is for selecting terminology and default calculation settings according to industry types.
Admin categories (Admin menu) •
P6 users can add or delete types and categories for baseline, expense, WBS, document, risk, and notebook. Types will be used for defining the type of each item.
•
Units of Measure – Users can add or delete units of measure for weight, length, area, and volume. Units defined in this option will be used as units of resources, especially for materials.
Currencies (Admin menu) •
P6 users can add or delete currency types. For viewing monetary values in the schedule or report, you can select Currency in the Currency tab of User Preferences in the Edit menu.
User preferences (Edit menu) •
Time Units – For choosing time formats for resources and activities. Units Formant is for setting the time unit of resources and Durations Format is for setting the time unit of activity duration (see Figure 34). If you select Day for Durations Format, activity durations will show day-based durations.
•
Dates – For selecting date format, 24-hour format, 4-digit year, and etc.
•
Currency – For choosing a currency for viewing monetary values. Figure 34 – User preferences dialogue box
FIFTEEN MUST-REMEMBER PRIMAVERA P6
KEYBOARD
SHORTCUTS
IN
There are 29 keyboard shortcuts in Primavera P6 PPM (version 15.1). Among them, the following 15 shortcuts are most commonly used: •
Commit changes to the database – F5
•
Refresh screen data from the database – F10
•
Schedule – F9
•
Re-schedule – F9 + Enter
•
Level resource – Shift + F9
•
Spell-check – F7
•
Search – Ctrl + f
•
Search and replace – Ctrl + r
•
Undo last action – Ctrl + z
•
Fill down a value – Ctrl + e
•
Select all objects – Ctrl + a
•
Delete the selected objects – Delete
•
Cut/Copy/Paste an object – Ctrl + x / Ctrl + c / Ctrl + v
SETTINGS FOR A NEW PROJECT Prior to creating a new project, you must organise the EPS of the Enterprise menu group. The EPS is the hierarchical structure of the database of projects, which helps P6 users group and organise projects in a manner meeting the organisation’s needs. When constructing EPS, it is recommended that the lowest level of EPS be rooms where various versions of a project will lie. It is very convenient to put all versions of a project under the same room, such as the latest baseline and old baselines, current version and backups, and reflection versions. Below are naming structures and sample names for each version of a project: •
Baselines: Project name + “B01” (baseline version) + purpose (e.g., approved) + date = “Korea High Speed Line – B01 – Approved – 05 Jun 2017”.
•
Backup: Project name + “Backup” + purpose (e.g., submitted) + date = “Korea High Speed Line – Backup – Submitted to client – 10 Aug 2017”.
•
Reflection versions: Project name + “Reflec.” + status (sent/from) + counterpart + date = “Korea High Speed Line – Reflec. – Sent – Seoul office – 20 Nov 2017”.
“Status” in the reflection version name indicates whether the schedule has been sent out or received. Reflection versions are created to update the schedule; a scheduler on a project management team creates it and sends it to counterparts at departments, field site offices,
and subcontractors, and they update the project progress and send it back to the scheduler. After comparing the updated file with the original and confirming there are no problems, the scheduler reflects it to the original. After creating a new project, you can set six options in the Project window – General, Dates, Defaults, Settings, Calculations, and Resources. If you cannot view any of those tabs, you can customise tabs. Many options for activities lie in the Defaults tab. The following options in the Defaults tab are related to schedule management tactics. (The options in the Defaults tab are for new activities only; thus, changing this setting does not affect existing activities.) •
Duration Type affects the correlation between duration, units/time (performance), and units. There are four types of duration, and each type is used for a different purpose – “Fixed Duration & Units” (FDU), “Fixed Duration and Units/Time” (FDUT), “Fixed Units” (FU), and “Fixed Units/Time” (FUT). FDU and FDUT are generally used in the construction phase, while FU and FUT are generally used for developing scenarios in the planning phase.
•
Percent Complete Type defines the actual progress of an activity. The option has three types – Duration, Physical, and Units. Under the fixed price type contract, Physical is recommended.
HOW DO P6 USERS SELECT DURATION TYPES? Duration type determines the relations between remaining duration, units assigned to activity, and remaining units per time as follows: •
Fixed Units/Time – This is used if the activity has fixed productivity output per time period. When the duration of an activity with this type increases, the amount of budgeted labour units also increases while resource units per time remain constant.
•
Fixed Units – This is used when the amount of the units is fixed. Decreased units per time causes the activity duration to increase. When a user updates the duration or units per time, the units remain constant.
•
Fixed Duration and Units/Time – This is used when the duration and resource performance have constraints.
•
Fixed Duration & Units – This is used when the duration and the amount of the resources have constraints.
In order to choose the appropriate duration type in accordance with schedule management tactics, schedulers must first understand following formula:
In the implementation phase: •
When duration is shortened, performance (Units/Time) should increase in order to complete the planned quantities (Units) on time [1].
•
When performance decreases, duration will increase [2].
•
When the quantity decreases, duration will decrease because a client will probably require to complete the tasks earlier [3].
On the other hand: •
When duration increases, performance will decrease [4].
•
When performance increases, duration will decrease [5].
•
When the quantity increases, performance should increase because a client generally will require to complete the tasks on time by increasing performance [6].
In the perspective of mentioned above, Fixed Units seems more desirable. Figure 35 demonstrates the correlation between duration, performance (units/time), and quantity (units). The basis activity is A0000 (Original) with 12 days, 32 units/time, and 384 hours (units). Figure 35 – Changes according to duration types
However, in terms of schedule management, Fixed Units is not a good choice because: •
Doubled Units/Time does not always mean double performance and schedulers do not care changes of Units/Time but those of durations or units.
•
Durations or units should not be changed unexpectedly because successor activity owners can hardly follow up predecessor activities’ change. The duration of the activity with Fixed Duration & Units type only will not change when units change, and vice versa.
To conclude, Fixed duration & units is recommended in the implementation phase, and is commonly used in managing schedules.
HOW DO P6 USERS CHOOSE PERCENT COMPLETE TYPES? Percent Complete is an estimate of the amount of work that has been completed on an activity. In Primavera P6, each activity must have one of the following Percent Complete types: •
Duration – Used when progress for the activity can best be reported based on original planned work days and scheduled work days remaining. In other words, if an activity had an original duration of 10 working days, and it is estimated that there are four work days remaining, the activity is estimated to be 60 % complete. This is computed as:
•
Physical – Used for activities whose progress can be assessed most accurately based on the complete of deliverables. This is calculated as:
•
Units – Used when actual work effort accomplished and actual work effort remaining can be used to accurately represent progress for the activity. For example, if an activity was allotted 100 hours of work and the contractor has spent 30 hours, the activity is estimated at 30 % complete. This is computed as:
Each activity must have one of the Percent Complete types in accordance with its task types. So, what type of Percent Complete should be assigned to each activity? To answer the question, it is necessary to consider the client’s point of view. Duration and units are not usually important for clients because:
•
Duration is not what the client wants to get, although Duration can be an element of the client’s requirements.
•
Units are the quantity of resources that a contractor will spend. On the other hand, there are some contract types that require monitoring units to estimate payment.
“Physical” in Primavera P6 represents deliverable for which the client has made contract and the client will pay in accordance with complete of deliverables. Progress data of “Physical” indicates EV in EVM in case of that Physical is selected in Activity complete option. Figure 36 illustrates the relations of progress data and deliverables. As previously mentioned, what client wants to get is the information about completed quantities (completed deliverables) on time and it will be indicated by means of EVM – EV and PV. PV is calculated from schedule (actually, activities loaded with resources) and EV comes directly from Activity complete that is indicated from one of Physical, Units, and Duration. For instance, if an activity has Physical for its Percent Complete type, value of Physical will be that of Activity complete for the activity. When schedule is updated, values of completed deliverables, spent units, and elapsed time will be progress of Physical, Units, and Duration respectively. In conclusion, “Physical” of Percent Complete is frequently recommended in construction projects. Figure 36 – Relations of progress data and deliverables
If EV and activity percent complete are not linked together, please check EV preference in Admin Preferences at Admin menu (See Figure 37). Figure 37 – Earned Value preference
When choosing an activity percent complete type, you must check the activity characteristics.
•
Physical is generally used to assign Percent Complete Type. Since there is no standard measurement method for Physical, you must determine, with the client, weight for each process. If you cannot use steps in the schedule, please check the option “Activity percent complete based on activity steps” in Calculations in the Project window.
•
Units is usually used for Cost-Reimbursement Contracts that provides for payment of allowable incurred costs.
•
Duration is assigned to the activities that are not component of deliverables and do not have resources. It is generally used for activities in Labour-Hour Contracts.
COLUMNS AND LAYOUTS Since Primavera P6 users change columns set in the activities table frequently, the columns should be saved as a layout. Saved layouts help P6 users save time when setting columns; however, users tend to make lots of layouts unnecessarily for columns set. If there are numerous layouts, it may be difficult for users to determine which columns a layout has based on the layout name. In that case, it is best to print out a layout list with each item’s columns set and keep it on your desk for reference. Below are the columns and filter sets needed in each layout. Note that all layouts must have an Activity ID and Activity Name. When developing a new schedule, use: •
Remaining duration: To view the duration assigned to activities.
•
Start: To view the assigned start date of activities on the basis of schedule logic.
•
Finish: To view the assigned finish date of activities based on the remaining duration of activities.
•
Calendar: To assign a calendar to activities.
•
Activity codes: To assign activity codes to activities.
When analysing constraints, use: •
Primary constraint: To view the primary constraint assigned to activities.
•
Primary constraint date: To adjust the primary constraint date assigned to activities.
•
Secondary constraint: To view the secondary constraint assigned to activities.
•
Secondary constraint date: To adjust the secondary constraint date assigned to activities.
When analysing the critical path, (filter critical activities by selecting Critical in the filter dialogue box), use: •
Performance % compete: To view the current progress.
•
Actual duration: To view the actual time spent on activities. This is the total working time from the actual start date to the data date for in-progress activities, or the actual finish date for completed activities.
•
Remaining duration: To view the amount of time to be spent on activities.
•
Start: To view the assigned start date of activities on the basis of schedule logic.
•
Finish: To view the assigned finish date of activities based on the remaining duration of activities.
•
Total float: To view the level of criticality of activities.
To look ahead, filter activities using the filter dialogue box as shown in Figure 38, and set columns to “When analysing critical path”. Figure 38 – Filtering activities to look ahead
When comparing a schedule with the baseline, use: •
Performance % complete: To view the current progress.
•
At completion duration: To view the forecast duration of activities.
•
Start: To view the assigned start date of activities on the basis of schedule logic.
•
Finish: To view the assigned finish date of activities on the basis of the remaining duration of activities.
•
Schedule % complete: To view the baseline % complete status of activities.
•
BL project duration: To view the baseline duration of activities.
•
BL project start: To view the baseline start date of activities.
•
BL project finish: To view the baseline finish date of activities.
•
Variance – BL project duration: To view the difference between activities’ baseline durations and the current schedule.
•
Variance – BL project start date: To view the difference between activities’ baseline start dates and the current schedule start date.
•
Variance – BL project finish date: To view the difference between activities’ baseline finish dates and the current schedule finish date.
When analysing near-critical activities, filter activities using the filter dialogue box as shown in Figure 39, and set columns to “When analysing critical path”. Figure 39 – Filtering near-critical activities
When assigning resources, use: •
Performance % complete: To view the current progress.
•
At completion duration: To view the forecast duration of activities.
•
Start: To view the assigned start date of activities based on schedule logic.
•
Finish: To view the assigned finish date of activities on the basis of the remaining duration of activities.
•
Budgeted labour cost: To view the cost of labour resources assigned to activities.
•
Budgeted total cost: To view the cost of labour and non-labour resources as well as resources assigned to activities.
When setting columns in the resource tab, use: •
Resource name: To view resource names.
•
Remaining units/time: To view the amount of resources per time available to work on an activity.
•
Price/unit: To view resource prices.
•
Budgeted units: To view planned units to be spent on an activity.
•
Actual units: To view actual labour units spent by resources on an activity.
•
Remaining units: To view outstanding labour units to be spent by resources on an activity.
•
Budgeted cost: To view the planned cost of resources assigned to activity.
•
Actual cost: To view the cost incurred by resources assigned to an activity.
•
Remaining cost: To view the outstanding cost to be spent by resources assigned to an activity.
When reviewing Earned Value, use: •
Performance % complete: To view the current progress.
•
At completion duration: To view the forecast duration of activities.
•
Start: To view the assigned start date of activities based on schedule logic.
•
Finish: To view the assigned finish date of activities on the basis of the remaining duration of activities.
•
Schedule % complete: To view the baseline % complete status of activities.
•
BL project duration: To view the baseline duration of activities.
•
BL project start: To view the baseline start date of activities.
•
BL project finish: To view the baseline finish date of activities.
•
Planned value cost: To view the budgeted cost of work scheduled.
•
Earned value cost: To view the budgeted cost of work performed.
•
Actual cost: To view the actual cost of work performed.
•
Schedule variance: To view the difference between achieved schedule performance and planned schedule performance.
•
Schedule performance index: To view how the progress of work performed compares to the progress of work planned.
•
Cost variance (or Accounting variance): To view the difference between the spent cost of work performance and planned cost performance.
•
Cost performance index: To view how the cost of work performed compares to the cost of work planned.
•
Estimate at completion cost: To view the forecast cost at completion of activities.
•
Budgeted at completion: To view the planned cost at completion of activities.
•
Variance at completion: To view the difference between the forecast cost at completion of activities and the planned cost at completion of activities.
•
To complete performance index: To view the projection of the future cost performance required to achieve either BAC or EAC cost.
HANDY TIP – FINDING MISSING ACTIVITIES When opening your project, you may find that all activities are missing. They are actually not missing. Check the filter status as shown in Figure 40. If the status is not “All Activities”, check “All Activities” in the Filters dialogue box (see Figure 41). Activities are never missing until you delete them.
Figure 40 – Filter status
Figure 41 – All activities
HANDY TIP – CUSTOMISING NAMES OF TIMESCALE You can customise the names of timescale in the chart area as shown in Figure 42 – M 1, M 2, and M 3. •
Close Primavera P6.
•
Find the file “comStrins.en-us” at c:\Program Files (x86)\Oracle\Primavera P6\P6 Professional\Languages.
•
Backup the file before opening it.
•
Open the file and find the strings “4251|JAN”.
•
Change “JAN” as you want like “M 1”, for example, as well as other month names.
•
Run Primavera P6. You will find the names of the months have changed.
•
You can customise other strings by changing strings in the file. Figure 42 – Customising timescale
PLANNING & PUBLISHING
Strategies in planning In planning process, a Project Master Schedule is developed. For better schedule development, schedulers should take the following strategies into account: •
Schedule methodology, technique, and tools should be documented and approved for efficient communications.
•
Schedulers should spend enough time defining the work scope and developing WBS to reduce the need for rework on scheduling. In other words, if the work scope is changed or redefined, WBS and activities should also be changed or redefined.
•
WBS in a schedule should cover 100% of the scope. WBS is not a collection of the tasks but of the deliverables.
REQUIREMENT-ORIENTED PROJECT MANAGEMENT Beginners in Primavera P6 have difficulty scheduling not because they do not know schedule management theories or how to operate P6 but because they do not fully understand project management. To understand the properties of schedule management and apply them in the workplace, it is essential to look over the nature of project management first. Project management requires various techniques and tools to tackle requirements suggested by a project owner, a client, or stakeholders. A construction project has a clear target building or infrastructure designed to provide a function or service, which will be delivered in terms of requirements for: (1) the object itself, (2) the object-related or project-related information produced during the project lifecycle (maintaining documents, drawings, and records), and (3) the manner of working. (1) Deliverables shall be completed with designed physical quantities meeting a predefined level of quality. (2) All documents (plans, drawings, specifications, calculations, etc.) and records produced during the project period shall be stored and maintained systematically, and the documents for maintenance work for buildings or infrastructure (plans, procedures, criteria, manuals, etc.) shall be prepared. (3) All activities relevant to the project shall be performed according to laws, regulations, HSE (Health, Safety, and Environment), procedures, codes, etc. Figure 43 – Satisfying client’s requirements
Figure 43 shows an example of a flow satisfying a client’s requirements in a construction project. The client will be satisfied with deliverables that meet appropriate quantities and quality codes, and these should be completed as planned. Appropriate quantities will be achieved by design review, and “completed as planned” will be accomplished through schedule control. As for quality management, there are two categories – correctable and uncorrectable items – in the test and commissioning phase. An uncorrectable item, for example, would be concrete strength that cannot be estimated accurately after concrete work is completed. Even if concrete strength of structure could be measured correctly in the test phase, reworking columns or girders would cause serious problems for the contractor, as well as the client, if they later fail to meet a quality code. Thus, this type of work must be monitored, checked, and tested by a supervisor in the constructing phase. In the test and commissioning phase, punch lists will be made for items that have failed to pass the test, and these items will undergo corrective actions until they pass the test. On the other hand, a project manager will have the budget and time to complete a project. Even though budget and time can be defined as resources, they can be also constraints (requirements) for the project manager and project participants at the same time because a project has to be completed within the timeframe and budget defined by the contract agreement. Project management can be defined as a process by which to actualise the planned deliverables and tackle requirements. When a contract is settled between a client and a contractor, the client has the authority to be delivered the target building or infrastructure, and the responsibility to pay for it. The contractor has the responsibility to complete the required deliverables on time in a proper manner, and the authority to receive the amount of money stated in the contract. Therefore, from the contractor’s point of view, requirements can be categorised as follows: •
Deliverables – physical quantities satisfying quality codes, documents, and anything for stakeholders’ interests.
•
Constraints – budget, schedule (duration) and any required constraints from clients or stakeholders.
•
Manner of working – laws and regulations, HSE, and codes.
In dealing with scheduling and monitoring progress, schedule engineers should be most concerned with quantities, budget, and schedule. In order to understand the options set in Primavera P6, readers should remember that physical quantities belong to requirements for deliverables, while budget and schedule (duration) belong to constraints.
SCHEDULE-RELATED DOCUMENTS
REQUIREMENTS
IN
CONTRACT
Below are the major schedule-related requirements that you may find in contract documents: •
Submission of the Initial Schedule – This shall have detail tasks for the first four months (or six months) of the project, including an outline for the remaining period of the contract.
•
Submission of the Master Schedule – This shall have the Inception reporting, designing, procuring, manufacturing, constructing, fitting out, testing, and commissioning, as well as initial maintenance tasks, if necessary.
•
Submission of the two-month (or three-month) detail schedule – The contract shall submit the two-month detail schedule using rolling wave planning technique at the end of every month.
•
Methodology – Schedules shall be computed by CPM (Critical Path Method) using the Precedence Diagramming Method (PDM).
•
Software and version – Schedules shall be prepared using CPM scheduling software (Primavera P6 or MS Project).
•
Schedule Analysis Report (SAR) – SAR shall include assumptions, risks, constraints, WBS dictionary, etc.
•
Calendar – The calendar shall include all public holidays and non-work days. Nonwork days generally reflect weather conditions, such as temperature, snow, rain, and wind.
•
Activity duration limitation – Activity shall not have a duration of more than 20 work days (or 30 work days), for example.
•
Progress measurement methodology – The contractor shall suggest methodologies for monitoring, controlling and updating schedules.
•
Resource – Activities shall be loaded with resources.
•
Organisation Breakdown Structure (OBS) – An OBS dictionary with responsibilities
shall be prepared. •
Responsibility – The contractor shall assign activities to departments, engineers, field site offices and subcontractors.
•
Start-to-Finish (SF) relationship – Use of SF relationships shall be avoided.
•
Constraints – Only the constraints provided by the client shall be assigned to activities.
•
Work Breakdown Structure (WBS) – Schedules shall be organised in a logical WBS.
•
Activity number – Activity numbers shall reflect the high level of WBS numbers.
•
Activity code – If any activity codes are provided by the client, they shall be used in the schedules.
•
Monthly Progress Meeting (MPM) – MPM shall be held to review monthly progress and performance regularly.
•
Monthly Progress Report (MPR) – MPR shall be submitted covering all aspects of the execution of tasks: schedule (actually started and finished activities, and delayed activities and reasons), EV analysis (PV, EV, AC, ETC, EAC, etc.), photographs, issues of the three-month rolling schedule.
THE DOS AND DON’TS OF DEVELOPING A SCHEDULE It is important to establish dos and don’ts in developing schedules, and to share them with the schedule management team because schedule management requires schedulers to deal with a lot of schedule-related data in a limited time. Following are dos and don’ts that clients usually suggest for efficient schedule management: Activity •
Activity name – Since activities are tasks for work packages, they should have unique names that include a verb; for example, “Prepare shop-drawings for the fifth floor”. Additionally, work packages should clarify the target deliverable without verbs.
•
Less abbreviations in names – The more abbreviations in the names, the greater the potential for confusion. If you want to use abbreviations, share the abbreviation list with others.
•
Uniformity in naming structure – Standards should be prepared for developing activity descriptions.
Activity relationship •
Relationship – All activities should be linked to identify critical activities and calculate the project duration. Some clients suggest that the number of activities without predecessors and/or successors should not exceed 5% of the total activities, while others allow the project start and finish milestone to have one successor or predecessor
activity. •
Relationship types – There are four types of activity relationships (Finish-to-Start [FS], Start-to-Start [SS], Finish-to-Finish [FF], and Start-to-Finish [SF]), and some clients require that at least 90% of the total predecessor relationships to total activities be the FS type, while others ban the use of the SF type.
•
Lag – Some clients prohibit using lag, while others allow less than 5% of activities with lags.
•
Lead (negative lag value) – Since leads can distort the total float and the critical path, and cause resource conflicts, they are not allowed in the schedule.
Constraints •
Hard constraints (Must Start On, Must Finish On, Start On or Before + Start On or After, and Finish On or Before + Finish On or After) – Some employers maintain that more than 5% of the total activities are not allowed to have hard constraints because they prevent activities from moving forwards or backwards as per changes of predecessors’ dates.
•
Permitted constraints – It is recommendable to assign the permitted constraints not to activities but to milestones.
Miscellaneous •
High float – High float can be defined as the floats outnumbering 44 working days. Some clients allow less than 5% of the total activities to have high float.
•
High duration – High duration can be defined as the duration outnumbering 44 working days. Some employers allow less than 5% of the total activities to have high duration.
•
Splitting activities – Some scheduling software provides a feature for splitting activities; however, some clients require contractors not to use it because split activities can distort the critical path. Instead, contractors should separate an activity into two.
DECEPTIVE SCHEDULES ARE NOT ALLOWED Some skilled schedulers (claim-oriented contractors) use numerous methods to create deceptive schedules to their advantage in solving disputes, as follows: •
Illogical activity relationships – Schedulers can pull forward or push back an activity by assigning unnecessary relationships to activities.
•
Calendar manipulation – Schedulers can extend or shorten the calendar duration of activities by assigning inappropriate calendars to them.
•
Lead-lag manipulation – Schedulers can make change to the start date of an activity by
assigning lead or lag to relationships. •
Over-progressing – Schedulers can distort the total per cent of completion by overprogressing activities that are on the critical path but have large weight (budget).
However, if their intention is not for claims but to encourage the project team members to meet the project deadlines, manipulations may be excusable. To inspect and prevent deceptive schedules with evil intentions, clients should perform schedule validation and schedule auditing. •
Schedule validation is an external evaluation to ensure that a schedule is correct in its scope and assumptions, as well as free from pitfalls. Validation occurs when the initial or revised baseline schedule is submitted prior to the start of any tasks. An inspection should ensure that the schedule incorporates appropriate construction methods, calendars, production rates, and resource availability compatible with the environment, as well as review that its goal is meeting the project’s requirements in terms of scope, time and resources.
•
Schedule auditing should occur several times during the execution phase of the project in order to maintain transparency in the schedule by ensuring that the project has proceeded according to plan, and that the progress in the period has impacted the project completion date.
REQUIREMENTS FOR COUNTERPARTS From the standpoint of a scheduler who needs to exchange XER files and collect progress data, it is important to establish requirements to control the project schedule produced or updated by counterparts. Below are recommended requirements for counterparts to follow: •
Duration type of each activity should be “Fixed duration & units” because the dates of this type do not change when units and performance (units/time) change.
•
Percent complete types for each activity should be “Physical” because this type indicates the progress of deliverables.
•
Hours per time period in Admin preferences should be set to Primavera P6’s default because changing one of the options may change activity durations and dates.
•
Critical activities shall be on the longest path (scheduling option).
•
Activity ID and name should follow Activity ID structure and naming standards.
Exchanging XER files involves the risk of making your Primavera P6 database become entangled with global data coming along with XER files from your counterparts. Below are XER data that will update your database but you may not want to: WBS IDs and names, activity codes and code values, relationships to external projects, calendars, work products and documents, project expenses, issues and risks, and thresholds. Therefore, the following requirements should be added:
•
Activity codes should be Project level because Global activity codes can overwrite each other.
•
Calendars should be Project level because Global calendars with the same name can overwrite other project calendars.
Exchanging Excel files instead may prevent spoiling your database; however, you cannot import all data this way. Below are the data you can import (more data types can be imported in three areas – resources, resource assignments, and expenses): •
Activity area – Activity IDs and names, activity codes, actual start and finish dates, primary and secondary constraint and its dates, original and remaining durations, calendar names, WBS codes, activity status, percent complete type, activity % complete, variance-BL project labour and non-labour units, and variance-BL 1 labour and non-labour units.
•
Relationship area – Relationship type, predecessor and successor, predecessor free float, and lag.
IMPORTING P3 FILES INTO P6 Sometimes schedulers refer to or use historical schedules. What if you have a P3 format file and you are now operating only Primavera P6 (Version 8.0 or higher)? When no version of Primavera P3 is installed in your computer, the option for P3 importing in the Import dialogue box is not activated. To import P3 files to Primavera P6, follow the steps below: •
Search for W32MKDE.exe and other files in the website and download it in your computer. (The files may be zipped.)
•
When you unzip them, you will find the instruction file and other files.
•
Follow the instructions to make folders – C:\P3WIN, C:\P3WIN\P3OUT, C:\p3win\P3PROGS, C:\P3WIN\P3WORK, and C:\P3WIN\PROJECTS.
•
Follow the instructions to copy the files into the folders you made.
•
Copy the P3 file into \P3WIN\P3PROJECTS. If the file has a “.prx” extension, unzip it into the folder.
•
When you start Primavera P6, you can find the option for P3 in the Import dialogue box, which is activated (see Figure 44).
•
Import the P3 file into P6. Figure 44 – The activated option for importing P3 files
DATA BACKUP IS THE MOST IMPORTANT ACTIVITY FOR P6 OPERATORS! If you are in a busy editing period, it is very important to backup often because we all make mistakes, and some mistakes cannot be undone in Primavera P6. If you accidentally import a file updating your project, run a global change, or delete a large section of the schedule, you are in trouble unless you have a backup copy. Therefore, you should make a copy for backups whenever you have a chance. There are three data backup types: database copy, project copy, and reflection project creation. •
Database copy – Since the database in Primavera P6 contains all projects and settings, schedulers must backup the database every day by copying the database file. In SQLite, the database file name is PPMDBSQLite.db (C:\Users\[Computer name]\Documents). In SQL, the database file names are pmdb_DATA.mdf and pmdb_LOG.ldf, or pmdb$primavera_DATA.mdf and pmdb$primavera_LOG.ldf (64 bit – C:\Program Files (x86)\MSSQL\Primavera \MSSQL.1\Data, 32 bit – C:\Program Files\MSSQL\Primavera\MSSQL.1\Data). To copy the database file of SQL, you need to stop the SQL Server (PRIMAVERA) in the SQL Server Configuration Manager prior to copying it.
•
Project copy – Whenever analysing a project schedule, you must use the copied project because the Undo feature in P6 cannot cover all of your “Oops!” such as scheduling and resource levelling. You can copy and paste a project in the Projects window.
•
Reflection creation – This is similar to copying a project; however, it provides a powerful feature that allows you to merge a reflection with the source project if you determine that the reflection has no problems. Reflection provides a feature to compare the reflection schedule with the original schedule.
If you understand the detail relations between Primavera P6 and its database (see Figure 45), you will know how to deal with the P6 database properly. Primavera P6 is a software package that controls a P6 database, as SQL is controls a database in a database
management system. Figure 45 – Relations between software packages and database management system
ESTABLISHING A SANDPIT DATABASE It is a good idea to make a sandpit database where you can create or copy, simulate and perform any project you like. Another advantage of the sandpit database is that you can prevent your Primavera P6 database from becoming entangled with global data coming along with XER files from other companies or counterparts when importing them in your project schedule. You can import the XER files to your sandpit database and cleanse the imported project’s associated global data, then re-export and import them to your project database. It may seem like a lot of work, but you can process it automatically with tools like XER Manager or even Global changes. (Google the XER Manager for more information.) To create a sandpit database: •
Copy SQL database files as previously explained and paste them in the same folder with a different name.
•
Run the SQL Server Management Studio Express.
•
In the login dialogue box, input “SQL Server Authentication” for Authentication, “sa” for Login ID, and “Prima123Vera” for password.
•
Hit the “New Query” icon.
•
Input “EXEC sp_attach_db@dbname = N‘[database name]’,” at the right section.
•
Input the second query “@filename1 = N‘[path name and file name]’”.
•
Input the third query “@filename2 = N‘[path name and file name]’”.
•
Save, close and rerun the SQL Server Management Studio Express. Figure 46 – Login dialogue box
•
Check whether a new database has been created and close it.
•
Run Primavera P6 and click the button, as shown in Figure 46, to display the Edit database connections dialogue box.
•
In the Edit database connections dialogue box, hit Configure and you will see the Database configuration dialogue box, in which you can input the Database name for Database alias, and select Microsoft SQL Server for Driver type.
•
In the next dialogue box, “Configure SQL Server Connection”, input “[computer name]\PRIMAVERA” for Host name and Database name.
•
In the next dialogue box, “Enter Public Login Information”, input “pubuser” for Username and “pubuser” for Password.
•
In the next dialogue box, “Validate Database Connection”, click Next.
•
If you see the message “Connection Successful!”, hit Finish.
•
Now you will see a new database in the Edit Database Connections dialogue box. Select it and input a password.
Note that creating a new database with SQLite is much easier; however, the use of its features is limited.
EASY REGULAR BACKUP Here is handy tip for automated regular backups for those who cannot use Job Services in Primavera P6. If you follow these steps, you can make your computer work for you (it works in Primavera P6 8.x and up).
•
Be aware of the project IDs that you want to make XER files. You can check the project IDs in the Projects window in Primavera P6.
•
Create a new text file (.txt) and input the code below. You have to change “XXXXX01” and “XXXXXX-02” to the project IDs that you want to back up. If you want to back up more projects, just add the line “
XXXXXXX”.
•
Your backup file will be saved with a name according to the line “C:\pathto\yourfile.xer”. Change the path and the name in the line as you like, and then save it.
•
Rename the file with the extension .xml.
•
Create a new text file (.txt), input the code below with no spaces between lines, and save it as follows:
(1) Primavera P6’s path and file name. If the Windows system is based on 32 bit, the path is C:\Program Files\Oracle\Primavera P6\P6 Professional\PM.exe (2) Login Name (you can see it when you log in to Primavera P6) (3) Password (4) Database name (you can see it when you log in to Primavera P6) (5) The path and the name of XML file that you made. (6) The path and the name of the log file that will be created while executing. You can check any errors with this file. •
Rename the file with the extension .bat and run it.
•
After executing the batch file (.bat), open the log file and check it. If you see the message “Returning Exit Code: 0” in the log file, the XER file has been exported from the database successfully.
If you want to run the batch file regularly and automatically, you can set Windows Task Scheduler to do so.
HANDY TIP – FINDING OUT WHO HAS CHANGED A SCHEDULE IN PRIMAVERA P6 You may have had the experience of having one of your colleagues make changes to your project schedule without leaving any comments in a Primavera P6 notebook. In that case, you can find out who did it. Add the following columns to your layout – Added by, Added date, Last modified by, and Last modified date, as shown in Figure 47. They will show you who has made changes to the schedule. Figure 47 – Adding columns
Define scope and develop WBS WBS is a product-oriented grouping of project components that defines the total scope of the project. Schedulers should spend enough time studying the work scope to minimise rework on WBS development because redefining WBS also requires rework on activities. Prior to defining scope and developing WBS, a code of accounts (COA) should be prepared. COA is a project management tool which assigns a code made from numbers, letters, or a combination of the two to every element on the WBS, OBS, etc. COA allows you to easily identify components, and is best used in PMIS.
ADVANCE PREPARATIONS Prior to developing the schedule, a scheduler should prepare or define some elements as necessary. Below are the elements that the schedule team should prepare or define to keep the integration of a schedule: •
Resources information – Information for resources needed in a project can be obtained from a Bill of Quantity (BOQ), drawings, etc. Resources are classified into three types in P6 (labour, non-labour, and material). In terms of procurement, they can be categorised into two types: secured resources (staff and machines), and the resources to be hired, purchased and leased.
•
OBS – OBS should not be limited to a project team, but include any organisations and stakeholders that can affect a project schedule.
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Cost accounts sheet.
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Activity codes – These are used to classify and organise activities on the basis of specific categories (disciplines, construction sections, phases, locations, etc.). Accordingly, they can play a role as WBS codes, OBS codes and cost accounts. Assigned activities with activity codes can be grouped, sorted, filtered and summarised in P6.
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Standardised Steps for Physical type activities – Project progress will be monitored based on the progress of Steps assigned to activities.
When using Primavera P6 EPPM, it is important to limit user privileges at the EPS and WBS levels.
DEFINE SCOPE AND STRUCTURE (WBS)
DEVELOP
WORK
BREAKDOWN
To define the work scope, a planner will study the contract agreement, drawings, specifications, and any other related documents. After the work scope is clearly defined, it will be decomposed into WBS. The level of detail for WBS depends entirely on the size and characteristics of a project, as well as the organisational structure. There are two
things to consider in developing WBS: WBS should be as simple as possible to help the project participants comprehend whole components of the project; when decomposing the work scope, the lowest levels (Work Packages) should be countable and assignable: •
Countable – Work Packages should be clear. For instance, “Planning a new transportation system” is not specific. Instead use, “Developing a Feasibility Study” or “Establishing an Environmental Impact Assessment”, for example.
•
Assignable – A work Package should be assigned to only one team (team leader) or one person in order to clarify where the responsibility lies.
Note that it is impossible to add WBS values at the top level, which is automatically named with the project name in the WBS window in Primavera P6, even though P6 users can create WBS by clicking Add and organise it by hitting the left and right arrow keys on the Command bar to promote and demote, as well as the up and down keys to move up or down.
HANDY TIPS – VARIOUS WBS DEVELOPMENT METHODS To build the optimised structure, WBS will be revised frequently in planning phase. If you build it in MS Word using Outline before entering it into P6, you can easily revise it as many times as you like. Another advantage of creating WBS with MS Word is that you can share it in compatible formats for others to review. Below are the steps to create it in MS Word (2013 version): •
Choose Outline in the View menu.
•
Put the cursor on the line or the sentence that you want to level up or down.
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Hit the Tab button on the keyboard to level down, or press Shift+Tab to level up.
You can move sentences using icons in the Outline Tools, or by dragging and dropping using the mouse. Figure 48 – Outline view of MS Word
Another approach to WBS is to create it in Excel and import it into P6 using SDK or XER Parser. Excel files for the SDK add-in and XER Parser are available on the websites.
ORGANISATION
BREAKDOWN
STRUCTURE
AND
RESPONSIBILITY ASSIGNMENT MATRIX OBS is a hierarchical model describing the established organisational framework for a business or project. Since every work package has to be assigned to a team, department, or staff, it is best to develop a responsibility assignment matrix (RAM) which shows the responsibility assignments of work packages, as shown in Figure 49. RAM can be also used to determine whether or not all work packages have been assigned. Figure 49 – Responsibility assignment matrix
DEVELOPING SCHEDULE MANAGEMENT DOCUMENTS Contractors on construction projects over a certain size need subcontractors – no individual company fills all disciplines and trades. Since projects involve many participants, miscommunications can occur, and schedules can be created in different (non-standardised) formats. Below are recommended documents and guidelines to help schedulers integrate schedules and people communicate efficiently: •
Schedule Management Plan – This should contain an introduction to the plan, work scope of schedule management, definitions and abbreviations, roles and responsibilities, project overview, WBS, Cost Account Structure, OBS, the schedule management strategy including schedule management levels and schedule controlling procedures, schedule-related risks analysis and management, schedule management software and systems, and schedule-related reporting and communication methodologies.
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Schedule Controlling Procedures – As mentioned earlier, these will include schedule development procedure (SDP), progress measurement procedure (PMP), and schedule change procedure (SCP). SDP introduces processes for developing, reviewing and approving schedules, as well as the roles and responsibilities of each participant. PMP illustrates how to monitor project progress, gather progress data, and control and update project schedules. SCP mainly focuses on responsibilities for proposal, review and approval for changing the master schedule.
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Schedule Development Criteria – This aims to maintain the integration of the schedule format and will be used not only by the schedule management team but also by subcontractors. Therefore, the criteria should reflect the requirements provided by the client, plus any requirements to control subcontractors’ schedules. It supplies
guidelines for the qualifications of lead scheduler, schedule software and version, activity number format, activity name format, limitation of activity duration, use of activity relationships, lag and lead (negative lag), use of constraints, and revision control of schedule. •
Schedule Assessment Checklist – This should be developed for the review of CPM schedules made by subcontractors.
Each document should be updated as needed and have, at minimum, its own document number, revision number, creation date, drafter and approver.
Develop activity list and sequences When creating a draft schedule, it is important to identify critical items that will affect developing activity list and sequences. •
Process – The physical or procedural sequences of tasks, activities performed by organisations outside the contract company (e.g., local government and third party vender), and essential advance preparation and activity sequences for performing tasks with ease.
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Resources – The expected lack of resources and efficient use of resources (e.g., machine rental).
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Environmental factors – These could include constraints of the working area (e.g., narrow space or crowded area), or expected opposition from residents or NGO (NonGovernmental Organisations).
RECOMMENDATIONS FOR ACTIVITY NUMBERING AND NAMING STRUCTURE Before beginning activity development, the scheduler should prepare the standard activity numbering (ID) and naming structure to ensure the integration of activity numbers and names. You will see numerous ID types and code types used to identify data in Primavera P6, but what are the differences between them? IDs are unique names of items such as activity ID, resource ID, and project ID, while codes are used to classify items, and include activity code, resource code, etc. When it comes to an ID for a task-dependent activity, as well as fragnet for delayed activities, it is recommended that activity IDs have two halves: •
The first half of an ID should have letters that are parts of WBS, where the activity belongs.
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The second half of an ID should have numbers showing the sequence of an activity.
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Numbers should start with 100 or 1000 to leave room from 000 to 099 or 0000 to 0999 for non-task dependent activities (milestones, level of effort [LOE], etc.).
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If you want to use long activity IDs, you should change the maximum number of activity IDs in the ID lengths tab under Admin preferences in the Admin menu. Figure 50 – Adjusting activity ID maximum characters
For an ID of non-task dependent activities: •
The first half should have letters indicating which WBS the activity belongs to.
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The second half should have numbers between 000 to 099 or 0000 to 0999.
When it comes to naming a task-dependent activity: •
Use verbs plus an object’s name and location. If the object is for the whole of the project, its location is not necessary.
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As mentioned earlier, avoid using abbreviations whenever possible. If you want to use them, make an abbreviation list and share it with all participants who deal with the project schedule to avoid misinterpretation of activity names.
When naming non-task dependent activities, as well as fragnets for delayed activities: •
Use capital initials followed by a dash “ – ” for each activity in the first part of the activity name to distinguish them from normal activities, for example: SM (Start milestone), FM (Finish milestone), LOE, SUMMARY (WBS summary), DELAY (fragnet).
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Put descriptions after the dash, for example: SM – NTP, LOE – GVB10010 to GVB10050 (activity IDs or names), SUMMARY – KEGVB (WBS ID or name), DELAY – GVB10030 (activity ID or name).
WAYS TO RENAME ACTIVITY IDS Schedulers may want to rename activity IDs when: •
The order of activity IDs does not match the activity sequences. If a scheduler created an activity with ID “A130” for construction and later made ID “A140” for design, he or she may want to rename one of the IDs to keep schedulers from misunderstanding activity sequences; design has to begin prior to construction.
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There is no room between two IDs to insert an activity. If a newly created activity should be inserted between two activities (A110 and A111, for example), schedulers may want to change them.
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Activity IDs are not systematic. If there are activities with different ID structures in a WBS, such as A110, CHG32, T54KTR97, etc., schedulers should probably change them immediately.
How can you prevent or minimise the need to rename activity IDs? Here are some tips: •
Prepare criteria suggesting standard activity ID and naming structure.
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Increase the “Increment” of Defaults tab in the Project window. The default value is 10, but 100 is preferable in the planning stage.
In the following example, WBS B has some activities with an incoherent set of ID numbering: WBS A – A1010, A1020, A1030, A1040, and A1050; WBS B – A1070, A1080, A1200, A1300, and A1400; WBS C – A1110, A1120, and A1130. If you want to renumber the activities of WBS B to align them with those of WBS A and WBS C, you can “Renumber Activity IDs” (see Figure 51): •
Select all activities of WBS B, right-click the mouse, and click “Renumber Activity IDs”.
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Choose options in the Renumber activity IDs dialogue box, select “Auto-number” and define Prefix with a letter (for example, “B”) that any activity does not have in order to avoid duplication.
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Hit OK.
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Renumber them again to align the renumbered activity IDs, and click “Commit Changes” in the File menu to refresh the database and avoid making duplications for A1070 and A1080.
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Right-click the mouse and click “Renumber Activity IDs” again. In the Renumber activity IDs dialogue box, select “Auto-number”, and define “A” for the prefix and input “1060” for the suffix.
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Hit OK.
If you have a lot of activities to renumber, you can use Export as follows: •
Export activities from Primavera P6 to Excel and change activity IDs in Excel.
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Delete the activities being changed from P6.
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Import the new activities from Excel to P6. Check whether each activity has a WBS ID before importing. If it does not, it will lose its WBS ID in Primavera P6.
If you want to export activities with a small number of data, there is an easier way. Rightclick the mouse in the activity table, and you will see the “Export to Excel” menu, as
shown in Figure 51. Click it, and save the Excel file. Figure 51 – Right-click
CREATING AN ACTIVITY LIST (OR DRAFT OF A SCHEDULE) AND SEQUENCES UNDER A WORK PACKAGE While WBS development is a process of decomposing the work scope, activity development is a technique for defining the processes of tasks (work packages); anyone who is trying to develop activities should understand the process involved in tasks. Before creating an activity list, milestones should be defined. Milestones are certain key events; they represent important immediate goals with the network. A milestone has zero duration, and is typically used to represent the beginning or end of a group of activities. Project documents may identify some, not all, milestones that a contractor is required to track and report. There are two ways to develop an activity list (or draft of a schedule). The first one is that the scheduler prepares activity list by himself referring to a project master schedule of other similar projects, if possible. The draft of the activity list (or draft of the schedule) will require the review of departments or engineers. The second way involves departments or engineers preparing their own activity lists according to assigned work packages. There are six types of activities in Primavera P6: •
Task dependent – This is used when the work needs to be accomplished in a given period regardless of the assigned resources’ availability. The activity’s resources are scheduled to work according to the activity calendar, and the duration is determined by the assigned calendar’s workweek.
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Resource dependent – This is used when the work is to be accomplished depending on the assigned resources’ availability. The activity’s duration and resources are scheduled according to the primary resource’s individual calendar. This is typically used when multiple resources assigned to the same activity can work independently.
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Start milestone – This is used to mark the beginning of a phase or to communicate project deliverables. This activity is a zero duration activity with a start date only. Constraints and expenses can be assigned to this activity type, but roles or resources cannot.
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Finish milestone – This is used to mark the completion of a phase or to communicate project deliverables, such as final inspections, etc. This activity is a zero duration activity with a finish date only. Constraints and expenses can be assigned to this activity type, but roles or resources cannot.
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Level of effort – This is a summary activity which summarises the earliest start and latest finish dates of its predecessors and successors. It is typically used for ongoing tasks dependent on other activities, as its duration is determined by its predecessor or successor activities. It should be noted that constrains cannot be assigned to this activity type.
•
WBS summary – This is used to roll up dates, duration, and per cent complete values for a group of activities that share a common WBS code level. This is similar to a level of effort activity, but provides more summarisation functionality.
Schedulers sometimes ask themselves how many activities are appropriate for a project. There is no correct answer because the number of activities in a project depends entirely on the project’s size and characteristics, as well as the number of staff who will deal with schedule data. Some say 3,000 activities per scheduler is reasonable; however, the scheduler’s job scope varies with each project.
SETTING STEPS Prior to assigning steps, you have to do two things. First, you should prepare standard steps for tasks that have weight (percentage), and have them approved by your client. If your client has no preference, you can establish them yourself. Second, check the option “Activity percent complete based on activity steps” in “Calculations” tab of the Project window. There are two ways to create steps: by using a step template, and by setting steps directly. Below are the processes for creating steps: •
Go to Activity step templates (Enterprise menu) and you will see dialogue with three sections. (see Figure 52)
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Hit the Add button on the right side and create a step name.
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Add as many numbers of steps as you like by hitting the Add button, name them, and assign weight to each step. You can make more step groups by clicking the Add button.
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When you finish making steps, click Close, and then go to the “Step” tab in the Activity window.
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Select an activity you want to assign, hit Add from template, and choose a step template. Now you can see steps in the steps tab. Figure 52 – Activity step template dialogue
HANDY TIP – IMPORTING DATA FROM EXCEL TO P6 Importing Excel files into P6 is useful; however, Primavera P6 does not recognise data without an apostrophe (‘) in front of each cell in Excel. Thus, when you create data, you have to add apostrophes manually. “ASAP Utilities” is a powerful Excel plug-in that offers many features, such as the ability to add apostrophes to cells by means of ASAP Utilities (see Figure 53). Of course, you can also do this in Excel by using Text to Columns in the Data menu of ASAP Utilities. Figure 53 – ASAP Utilities
WBS SUMMARY ACTIVITIES AND LEVEL OF EFFORT (LOE) WBS summary activity is used to summarise all activities belonging to the same WBS. If you do not have enough time to assign all activities with resources in a project but want to assign resources roughly and make S-curve quickly, you can use a WBS summary activity
by assigning it with all resources belonging to the WBS. A LOE activity’s duration is dependent on its predecessor and/or successor activities, so it is usually used to summarise several activities. LOE can be used for many purposes, and many schedulers use it for expenses, such as travelling expenses. If you want to assign indirect cost (expense, for example) that is not assigned to a specific activities, you can make a LOE activity and assign it with expenses. When naming the LOE activity, it is recommended to indicate the range of linking, for instance, “A1010-A1530”.
USING FILTERS EFFICIENTLY A commonly used menu in Primavera P6 is filter, which helps narrow down the range of activities displayed in the activity table. Figure 54 shows default filters commonly used by schedulers, which cannot be deleted or modified. Some of them are currently used for bar chart settings. Figure 54 – Default filters
If schedulers create a filter (see Figure 55) to fill a gap in the default filters, they can save time by using combinations of filters, selecting options of Filter dialogue box and selecting multiple filter sets (see Figure 56). Figure 55 – Examples of user-defined filter sets
Figure 56 – Filter dialogue box
Below are example using combinations of filters – multiple choice filter set: •
To filter activities that are both design activities and critical activities, select “All selected filters” in the filters dialogue box, and then check Item [2] from the default filters (Figure 54) and Item [d] from the user-defined filters (Figure 56).
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To filter activities that are milestones and will start or finish within three months, select “All selected filters” in the filters dialogue box, and check Item [6] from the default filters and Item [a] from the user-defined filters.
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To filter activities that are near-critical activities or have free float, select “Any selected filter” in the filters dialogue box, and check Item [b] and Item [c] from the user-defined filters.
Loading resources The purpose of resource loading on activities is to compute activity durations and identify resource constraints (Max units) in the planning phase, and to document financial records for analysis (cost management and progress monitoring) in the performing phase. There are two types of resource allocation methods: top-down and bottom-up. The former is mainly used in the planning phase and the latter is used in developing schedules. To load resources to activities, (1) create resources in the Resources (window) of the Enterprise menu, (2) assign them to activities in the Resources tab of the Activities window, and (3) review resource assignments in the Resource assignments (window) of the Project menu.
PROPERTIES OF RESOURCES There are three types of resources in Primavera P6 – labour (reusable), non-labour (reusable but depreciable), and material (consumable) – and they are procured as follows: •
Labour is man-power, and it can be procured by redeploying employed staff or employing new staff.
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Non-labour is equipment or subcontractors, and it can be procured by redeploying retentive machines, purchasing or renting new machines, or making contracts with subcontractors.
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Material includes all materials used in the project. Labour and non-labour share the same unit (h/d) while material has predefined units (e.g., ton, ea.). To use materials, you need to predefine units of measure in the option (Admin – Admin categories – Units of measure).
ROLE, RESOURCE AND WORK CREW Role in Primavera P6 is used as a plan for resource assigning, and it defines the level of skills required to perform a task, while resource is an actual item assigned to activities. There is a column for roles in the resources window in P6, which means that resources can be categorised into roles. Thus, roles can be regarded as a type of code for resources. A resources employed in a company are presented with its name, for example, John Doe, in P6 while a resource to be hired is presented with its role name, for instance, carpenter. Work crew is a collection of resources used to calculate activity durations based on performance and units (quantities). RSMeans is a good example of source for applying work crew. RSMeans is the industry source for accurate and expert information on materials, labour and construction costs, and crew. Each crew in RSMeans has a task description, crew composition, daily output (performance) and total cost. Schedulers compute activity durations as the quantity divided by performance (quantity per day) of crew. The information for quantities comes from the BOQ, which has resources (labour,
equipment, and material) and its quantities for each component of deliverables.
DEVELOPING A QUICK S-CURVE (TOP-DOWN RESOURCE ALLOCATION) If you want to make a quick S-curve for accumulated progress, payment or other items related to the contract price, you can use WBS summary activity. First, you need to create an activity with activity type WBS summary (Activities window – General tab – Activity Type) at the highest level of WBS assigned with the total amount of the contract price. The resource is used for showing price or cost only; the activity should have a resource curve that you can manipulate. If it is possible to divide the resource into the next highest level of WBS because the plan has advanced and costs are divided into the next level, create activities with activity type WBS summary at the next highest level of WBS and allocate resources to the activities. Next, adjust the budget of the activity (at the top) and the activities at the next level of WBS in order to meet the total amount of the project cost. As time goes on, the cost structure will become clear, and you can breakdown costs further and assign them to activities.
RESOURCE LOADING (BOTTOM-UP RESOURCE ALLOCATION) In bottom-up resource allocation, resources and quantities for activities can be obtained from Bill of Quantity (BOQ) and assigned to activities as follows: •
Analyse BOQ to define a coefficient (weight factor) since the total amount of a contract price consists of direct costs for tasks and indirect costs for offices (e.g., operating expenses) and headquarters (e.g., profit). The total amount divided by direct costs gives the coefficient.
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Reorganise BOQ in accordance with WBS (Work packages) and activities. There are three types of relations between activities and items on the BOQ: One to One – one activity represents one pay item on the BOQ; One to Multiple – one activity is the summary of many pay items (in other words, all viaducts of different sizes can be grouped under one activity; and Multiple to One – in many cases the BOQ has the total quantities, however in the schedule you need to split the work into more detailed sections. You do not need to load all resources to activities. Instead simplify each activity’s resources into at most two or three – labour and representative nonlabour/material. Representative non-labour or material means a resource with the highest cost among non-labours or materials; this will include other minor non-labour and/or materials’ costs, such that each activity has one or two resources (labour, or labour + non-labour/material).
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Multiply the quantity of resources by unit prices by the coefficient (weight factor) to determine the budget of each activity.
If you want to set a resource curve for each activity, duration type of an activity must be fixed – only “Fixed duration & units” and “Fixed duration and units/time” types can be assigned. Nevertheless, if you want to assign a resource curve to “Fixed units” and “Fixed units/time” type activities, you can use Expenses (Activity window – Expenses tab) instead. Expenses has three types of curve: •
Start of activity – The entire expense costs are accrued at the start date of the activity.
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End of activity – The entire expense costs are accrued at the finish date of the activity.
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Uniform over activity – The expense costs are accrued uniformly over the duration of the activity.
MONITORING THE PROGRESS OF PHYSICAL (DELIVERABLES), UNITS (RESOURCES) AND DURATION The progress of Physical (deliverables) can be monitored in terms of Planned Value Cost (PV), Earned Value Cost (EV), and Actual Cost (AC) in Primavera P6. What about units (resources)? Only labour has values for EVM monitoring – Planned value labour units, Earned value labour units, and Actual labour units. This is because that most work is done by people (labour), so labour units should be used as the basis for monitoring the progress of resources. When you status your project, you will see that Unit % complete and Duration % complete display their values rolled up to WBS and project level, as shown in Figure 57. Figure 57 – Progress
The Physical % complete and the Activity % complete cannot be rolled up at the WBS or Project levels because it is a value added manually by a user. If you want to obtain a rolled up Physical % complete, use Performance % complete instead. On the other hand, it is not possible to get an accurate value on summary level from Duration % complete because it computes project percentage based on baseline duration and remaining duration, rather than actual duration and remaining duration.
EASY RESOURCE LOADING AND PROJECT STATUSING
If a resource type or item is not important and the only purpose of resource loading is to monitor progress, you can manage it in a simple way as follows: •
Create a resource with $1/d price (rate) and then assign it to activities.
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Define Budgeted Units in P6 (Activities window – Resources tab. If there is no column for Budgeted Units, you can customise it in the Columns dialogue box) according to the total amount of the activity cost multiplied by the coefficient (weight factor).
•
If there is any resource that needs to be controlled due to, for example, supply constraints, create a new resource for the item with $1/d price and assign it to the activities. Define budgeted units for each considering the total amount of the activity cost.
The method mentioned above is known as the weighting factor method, and you can create just one resource to be used for all activities or multiple resources according to the project cost account (CA) structure if needed. If you want to classify costs into the project CA structure, you can compose a project CA structure in resources window and compute the totals of each CA. What if there is no precise budget for each activity so you cannot assign budget to them? In that case, the budgeted units will be defined on the basis of the activity duration until you convert it into other basis.
HANDY TIP – ERASING ALL UNITS ASSIGNED TO ACTIVITIES IN ONE GO If you want to erase all units of resources assigned in a project, you can use “Top Down Estimation” (Tools – Top down estimation) by inputting “0” in Estimated Units and hitting the Apply button. Figure 58 – Top down estimation
Developing activity duration and relationships The most important thing in schedule management may be activity relationships. Inappropriate relationships can spoil a project schedule and, moreover, it is very difficult to find an inappropriate relationship in a big schedule. Relationships, also referred to as logic ties or network connectors, hold the various activities and milestones together and are noted by arrows in the network diagram. •
Predecessor activity: An activity falling prior to another activity in an activity sequence. In Figure 59, Activity A is the predecessor activity of Activity B, and Activity B is the predecessor activity of Activity C. Figure 59 – Sequence of activities
•
Successor activity: An activity falling behind another activity in an activity sequence. Activity B is the successor activity of Activity A, and Activity C is the successor activity of Activity B.
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Driving predecessor activity: An activity affecting the start or finish date of the successor activity. In Figure 60, Activity A and B are the predecessors of Activity C, and they will be finished on 7 May and 12 May, respectively. Since Activity C can start only when all predecessors have finished, it will start on 13 May. In this case, Activity B is the driving predecessor activity for Activity C. When analysing a project schedule, this is an important technique for tracking the driving predecessor activities from the end of the activity sequence. You can see the driving activity check in the box of predecessors (see Figure 61). Figure 60 – Predecessors of an activity
Figure 61 – Predecessors of an activity
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Non-driving predecessor activity: An activity not affecting the start or finish date of the successor activity. Activity A is the non-driving predecessor activity in Figure 60.
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Lag: The duration assigned to a relationship between a predecessor activity and a successor activity to delay the start or finish date of the successor.
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Lead (negative lag): The duration assigned to a relationship between a predecessor activity and a successor activity to accelerate the start or finish date of the successor.
DURATION UNITS AND ACTIVITY DURATION ESTIMATION Some common methods and sources for deriving or enhancing duration estimates include: •
Parametric analysis: Schedulers use established standards, such as RSMeans, which suggest daily rates per required quantity based on historical records of accomplishment. Duration is computed as budgeted units divided by performance (units/day). The budgeted units can be derived from the BOQ.
•
Analogous analysis: Schedulers reflect experts’ experiences and judgements, and historical or related data.
When using analogous analysis, it is best to ascertain the optimistic duration, the most likely duration, and the pessimistic duration in order to apply PERT. Prior to estimating durations, a determination should be made as to the unit of measurement and level of accuracy required. From a schedule analysis perspective, it is highly recommended to make all duration time units alike within the same schedule. The reason for this recommendation is that mixing time units within the same schedule may result in slight differences and inconsistencies to float values that are internally calculated. For example, if a schedule management team sets eight hours per day as standard work hours for their schedules but a subcontractor sets twelve hours per day, schedulers in the team will find that activity durations are lengthened when they import the subcontractor’s schedule into their schedules at the ratio of 150% (= 12 / 8). This is because all duration data is stored on an hourly basis in the P6 database. When the subcontractor submits a schedule including an activity with duration of 10 days, its hourly duration is actually 120
hours. However, schedulers on the schedule management team will find that the activity takes 15 days because their duration basis is eight hours per day (120 hours / 8 hours per day = 15 days).
GRAPHICAL EVALUATION AND REVIEW TECHNIQUE (GERT) FOR INSPECTIONS AND TESTS GERT is a network development technique used in schedule management that allows probabilistic treatment of both network logic and estimation of activity duration. Since GERT allows loops between tasks, it is mainly used for the activities that depend on the results of inspections or tests. In other words, certain components need to pass a test, and if some of them fail, the rework will be performed again and again until successful, as shown in Figure 62. Figure 62 – Workflow of GERT
In this case, duration for the task should be calculated as the total duration of tasks (ready for test, test, and rework) divided by the probability of passing the test; however, because Primavera P6 does not provide this feature, schedulers should compute the expected duration of the task themselves, and take it into account when calculating activity durations.
SCHEDULE CONTINGENCY Schedule contingency (also known as schedule reserve or schedule margin) should be based on project risks and duration uncertainty, and be clearly identifiable when included within the master plan. For clarification, it should be understood that schedule float, which is a calculated value based on network logic, should not be considered as a schedule contingency. Thus, it should fall on the critical path. Figure 63 – Schedule adjustment based on CCPM
One of methods to secure schedule contingency is Critical Chain Project Method (CCPM), also known as Critical Chain Method (CCM). The purpose of CCPM is to secure a buffer, preventing project delay. This technique is based on methods derived from Theory of
Constraints (TOC), introduced by Eliyahu M. Goldratt. CCPM is based on the idea that task owners try to secure more time and resources than their tasks actually need (Parkinson’s law), and they will only start to apply themselves to a task at the last possible moment before its deadline (Student syndrome). Thus, a scheduler should collect slack time from each task and use it as buffer by putting it at the end of the schedule, as shown in Figure 63, to use as a measure by which to monitor project schedule and performance, and as a buffer in case of project delay. However, in applying CCPM to schedule management, there are some issues to consider: •
Generally, schedulers do not have the capability to judge the amount of slack time each task has. Only task owners (engineers) know the exact amount of slack time for their tasks, and it is unlikely that they will yield the slack. To secure the buffer, schedulers can reduce the durations of all activities by a ratio of 2% or 3%, for instance, in a lump.
•
Even though schedulers have succeeded in securing slack time from task owners, they may continuously experience project delay because there is no buffer mitigating delay at the beginning or in the middle of the schedule. If the delayed activity lies at the beginning of the schedule and none of its successor activities have slack, they may have to change their schedule. To ease off, schedulers should divide secured contingencies into smaller blocks of buffers, and insert them in the middle of the schedule at regular intervals.
SUSPENDING AND RESUMING AN ACTIVITY Sometimes schedulers feel the need to suspend and resume an activity. Only activities in progress can have suspend and resume dates; however, suspension is not recommended because it distorts total float. What if you need more suspending periods on an activity? MS Project provides such a feature, but Primavera P6 does not. If needed, you can use LOE. If a task will require three periods of suspension, make four activities linking them, with FS relationships and lag for the task. Then create an LOE activity and link it with the activities you have created. Assign a SS relationship with the first activity, and a FF relationship with the last one. Do not assign resources to the LOE activity; only do so for the four activities. Figure 64 – Suspending and resuming an activity
ACTIVITY RELATIONSHIPS BETWEEN WORK PACKAGES It is not difficult to assign relationships to activities belonging to the same work package, but linking activities belonging to different work packages can be complicated. To help establish reasonable relationships between activities, a scheduler should first develop a network diagram (see Figure 65). Figure 65 – Sample network diagram for a railway project
As you know, there are four types of relationships in scheduling – Finish to Start (FS), Start to Start (SS), Finish to Finish (FF), and Start to Finish (SF). FS relationship is frequently used to link activities; however, some P6 operators use FS for no other reason than to secure duration contingency in case of a schedule delay, even though they can use SS. When they need to recover delayed activities or finish tasks earlier, they can change the relationships from FS to SS with lags. In that case, the predecessor activities are just a precondition for the successors to start. Changeable relationships from FS to SS are called soft logic, and unchangeable relationships are hard logic. Soft logic is set for cost-saving and convenience in performing, so take note of all soft logics in UDF (User Defined Field) in P6 for easy search in case of finding points for fast-tracking to recover delayed activities. Below are examples of hard logics:
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Physical sequence: The structure of the second floor can be built only after that of the first floor is finished.
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Procedural sequence: Construction can begin only after the supervisor has approved the construction plan.
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Constraints in working: Permanent way work and catenary work in a railway project cannot start at the same time due to the narrow space.
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Constraints of resources: If there are five tasks that require a certain special machine and only one is available, the tasks should be processed one by one.
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Orders from the client or licensing from local government.
Below are examples of soft logics: •
Efficient use of resources: To utilise construction machines at multiple sites instead of buying additional machines.
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Convenience: It is reasonable to perform painting work before wallpaper work.
NEGATIVE VALUE LAG (LEAD) In many guidelines, negative value lag (lead) is prohibited in scheduling because it is hard to anticipate the successor’s start date. For example, suppose Activity B began ten days prior to the completion date of its predecessor (Activity A) and an unexpected event occurred two days before the completion date of Activity A, causing it to be delayed five days. Figure 66 – Change of activity relationship
In that case, Activity B should have started five days later because the completion date of its predecessor (Activity A) has been delayed five days. To prevent this situation, many guidelines recommend using SS with positive lag value, instead of FS with negative lag value, as shown in Figure 66.
HANDY TIP – REMOVING MULTIPLE RELATIONSHIPS Go to the relationship tab in the activity window and open the “Assign Successors” window. Select multiple activities in the activity window and those in activity assignment pop-up window. Then click the Remove button, as shown in Figure 67. Figure 67 – Removing multiple relationships
Assigning calendars Calendars are an important part of project schedules because they directly affect the duration of the project (specifically, the activities). Changing an activity’s calendar or Time period in Admin preferences can cause problems with activity durations from time to time. Thus, schedulers should fully understand the nature of both. When used properly by contractors, the calendar will demonstrate all working and nonworking days for a project. There are three types of calendars: •
Global calendars – These calendars are accessible to all projects in the EPS network and are available for all resources and activities.
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Resource calendars – These are used to determine when the resource can work, and the limits for that period are determined from the shift definition on that resource. They are used only for resource dependent activities.
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Project calendars – These are similar to global calendars, but are available only within a specified project.
It is best to create a new calendar for a new project, copying from a calendar, because sharing calendars may cause serious problems in scheduling. Calendars should be set in terms of three different time levels: working hours of the day, working days of the week, and non-working days of the year. (1) Working hours per day (e.g., 8 hours per day) – Select Total work hours/day and click Workweek in the calendar dialogue box, and then adjust work hours per day in the Calendar weekly hours dialogue box. (2) Workable days in a week (e.g., Monday to Saturday) – Select Detailed work hours/day, click Workweek in the calendar dialogue box, and then adjust Standard work hours in the Calendar weekly hours dialogue box. It is best to input eight (8) for workable days and zero (0) for non-workable days. (3) Non-workable days of the year (e.g., public holidays and non-working days due to bad weather conditions) – Select a day and click Non-work for non-workable days in the calendar dialogue box. Figure 68 – Defining workable hours and dates
WORKING HOURS PER DAY Since work time is not usually visible in the activities table or Gantt chart, schedulers sometimes make of mistake of combining working hours per day and Hours/Day in the Time periods in the calendar set. All durations in Primavera P6 are stored as hourly-based data, so when an activity is assigned a calendar that has, for example, eight work hours per day and the original duration of the activity is ten days, its original hourly duration is actually 80 hours. What if you want to change the work hours per day from eight to ten? First, you need to select a method by which to specify work hours/day. In the Time periods tab under Admin preferences in the Admin menu, you can see the option “Use assigned calendar to specify…” as shown in Figure 69. If you check the option, each assigned calendar will define the daily work hours of an activity individually. If you uncheck it and change Hours/day, you can see changed daily-based durations in the activity table immediately; however, hourly durations will remain the same. Figure 69 – Admin preferences
If you want to use a different daily work hour basis, you will need to define the work hours per day in both the Workweek and Time periods of each calendar, as shown in
Figure 70. If the Hours/day of Time periods is changed from eight to ten, work hours in the Workweek should be ten; workable days should have 10 hours, and non-workable days should have 0 hours. Figure 70 – Work hours per day
What will happen if work Hours/day in the Time periods of a calendar have been changed from 8 to 16, but daily work hours in the Workweek remain at 8? The durations of all the activities assigned with the calendar will be halved. For example, if the activity has 10 days as its original duration, its hourly duration will be 80 hours, as previously mentioned. When work Hours per day in Time periods is 16, the daily duration will be 5 (80 = 16 x 5) because Time periods is just the setting option to display work hours per day. If you select Hour for Durations format in the Time units tab under User Preference (Edit menu), you will never see changes to the original hourly duration in the activity table, even if Hours/day in Time periods are changed. If you want to make activity durations appear to be increased or decreased without changing their actual original hourly duration, you need only to alter work hours/day in the Time periods of the assigned calendar. (Note that as long as all participants who deal with the schedule count durations on a daily basis, duration changes due to changes in Time periods will cause real changes to activity durations.)
WORKABLE DAYS PER WEEK P6 users set workable days per week by defining work hours in the Workweek of the calendar set, as previously explained. When setting workable days, schedulers should consider the working environment of the site. Many countries have five work days per business week; however, construction projects usually allow for six or seven work days. When there are non-workable days in a week in the assigned calendars, the amount of delay of a predecessor activity does not always equal the delay days affecting the successor activity’s start date. Figure 71 shows an original schedule on the left, and a revised schedule on the right. The dark grey-coloured dates are non-working days. At first,
Activity A is scheduled to finish on 9 December and Activity B to start on 10 December. Later, Activity A has been delayed by two days and finished on 11 December. In addition, the start date of Activity B is delayed four days, even though the predecessor has been delayed only two days. The initial calendar duration (not the working duration) of Activity B was six days – from 10 to 15 December; its revised calendar duration is four days (reduced by two days). Figure 71 – Work days and calendar days
If you want to define the activities that are most affected by a calendar setting, you need only to calculate the difference between original duration and calendar duration: •
Calculate calendar durations (calendar duration = finish date – start date).
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Compute the difference between calendar duration and original duration (= calendar duration – original duration).
The benefit of identifying the most-affected activities by calendar setting is that it allows you to take them into account when analysing a project schedule or developing a recovery plan.
NON-WORKING DAYS OF THE YEAR To set non-workable days of the year, schedulers should collect two data – the national calendar for public holidays, and statistics for weather conditions. When it comes to weather conditions, it is helpful to use long-term statistics to increase probabilities; however, schedulers also have to take the latest local weather trends into account, due to climate change. Prior to setting non-workable days of the year, tasks should be classified according to their sensitivity to the impacts of weather conditions and holidays. You can find in the specifications the weather conditions affecting certain tasks. Below is a sample classification for impacts and tasks: •
Affected by low temperature – any tasks using water, such as concrete.
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Affected by rain – exterior paint work.
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Affected by wind – outdoor spray work, elevated work.
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Affected by no weather conditions – indoor work, tunnel work.
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Affected by holidays – review and approval process by client and central or local government.
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Affected by no weather conditions or public holidays – shipment.
Below are typical weather conditions and criteria under which certain work is prohibited: •
Rainfall – The daily total amount is 80 mm or more.
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Snowfall – The daily total amount is 50 mm or more.
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Wind – The daily maximum speed is 13m/second or more.
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Temperature – The daily average temperature is 0 degree Celsius or less.
Each task should be assigned an appropriate calendar type since each task is affected differently by weather conditions and holidays. Figure 72 shows sample calendar types where “X” means non-reflection and “O” means reflection. For example, Calendar C has non-working days for low temperatures. By the way, there should be as few calendar types as possible, to minimise interruptions in schedule analysis. Errors of float calculation can occur between activities with different calendar types. Figure 72 – Sample calendar types
For the countries that have warm temperatures throughout the year, you do not need to create a calendar that has non-workable days for low temperatures. In Middle Eastern countries, Ramadan (a fast and prayer period) is a considerable factor in setting a calendar. To reflect Ramadan in developing a calendar, additional review is required because not all foreign labourers follow it.
HANDY TIP – VIEWING 12 MONTHS AT ONCE Schedulers sometimes feel the need to view 12 months at once to quickly review the settings for non-working days throughout the year. There is a way. Download XERReader from the website and follow the steps below: •
Make an XER file of your project from Primavera P6.
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Open XER-Reader, hit Load XER, and find the XER file you created.
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After loading the XER file, select the project by clicking the drop button, and you will see the project information.
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Hit Calendar, and you will see a pop-up box.
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Input the year and select the calendar you want to see.
In the calendar sheet, you will see 12 months, with comments corresponding to greycoloured days (non-working days), green-coloured days (exceptions), and red-coloured days (inherited exceptions from the global calendar), as shown in Figure 73. Figure 73 – Calendar showing non-workable days over 12 months
Assigning constraints and activity codes Sometimes constraints interrupt scheduling and identifying critical path, for example, so schedulers should use as few constraints as possible. On the other hand, activity codes provide convenient functionalities for dealing with activity data, so schedulers should create, assign and use as many activity codes as possible.
ASSIGNING CONSTRAINTS Normally, an activity’s start and finish dates are defined by its relationships with predecessor activities; however, P6 users can adjust the dates arbitrarily by assigning constraints to the activities. Constraints should be assigned to activities only as required by the client. Most clients do not allow constraints because constrains affect an activity’s total float. Thus, any constraints assigned to activities must be documented with reasons and sources. There are nine constraint types in Primavera P6: •
Mandatory start – This forces early and late start dates of an activity or milestone to be equal to the constraint date, regardless of schedule logic and calculations.
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Mandatory finish – This forces early and late finish dates of an activity or milestone to be equal to the constraint date, regardless of schedule logic and calculations.
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Start on – This forces an activity or milestone to start on the constraint date, regardless of the calculations of the schedule, overriding schedule logic entirely.
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Start on or before – This places a deadline on the start of an activity or milestone and forces the activity or milestone to start no later than the constraint date.
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Start on or after – This sets the earliest date on which an activity or milestone can begin and forces the earliest start date to be equal to the constraint date; however, if the calculated start date is after the constraint, the later date will apply.
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Finish on – This is used to force an activity or milestone to finish on the constraint date, regardless of the calculations of the schedule.
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Finish on or before – This places a deadline on the completion of an activity or milestone, forcing the activity or milestone to finish no later than the constraint date.
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Finish on or after – This sets the earliest date on which an activity milestone can finish.
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As late as possible – This consumes the free float of an activity or milestone, and pushes the activity or milestone as late as possible without impacting the start of the successors (free float).
The nine constraint types fall into two categories in terms of their ability to fix the dates of
activities – soft constraint and hard constraint. Soft constraint allows an activity to move back and forth, or in one direction, and includes Start On, Start On or After, Start On or Before, Finish On, Finish On or After, Finish On or Before, and As Late As Possible. Hard constraint is the constraint (or combination of constraints) that allows no movement, or movement only within a given range. It includes Mandatory Start, Mandatory Finish, Start On or Before + Start On or After, and Finish On or Before + Finish On or After. If, for instance, you want an activity to start between 3 January 2017 and 17 January 2017, you need to set two constraints – select “Start on or after” in the Primary constraint on 3 January 2017 and “Start on or before” in the Secondary constraint on 17 January 2017, as shown in Figure 74. Figure 74 - Constraints
ACTIVITY CODES Activity codes are like tags, and help P6 users group and filter activities. They represent broad categories of information, such as phase, division of work (department or discipline), or location, building, floor, activity owner (responsible team, department, or staff). Activity codes can act like WBS codes, organising activities in a hierarchy and providing even more powerful features to organise them in various ways by combining several activity codes at the same time. Figure 75 shows an example of organising activities based on activity codes – Building and Floor. In grouping activities, the activity code for Building is located at a higher level than that of Floor in the image at left, and vice versa in the image at right. Thus, some P6 users prefer to use activity codes instead of WBS codes, which are less flexible and versatile than activity codes; however, there are features in WBS that activity codes cannot provide. You can summarise activities based on WBS, but not based on activity codes. Similarly, you can create a WBS summary activity in each WBS level, which shows a summary of WBS directly. Furthermore, most software packages share WBS format; thus, you can easily merge WBS outlines into other software, while activity codes can create problems. Figure 75 – Organising activities based on activity codes
Below are the steps to create activity codes and assign them to activities: •
Open the Activity codes dialogue box (Enterprise – Activity codes).
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Click Modify in the dialogue box and you will see the Activity code definitions dialogue box (See Figure 76).
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Hit Add in the dialogue box, name it, and then define Max length of code value for the activity code you created. Click Close.
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In the Activity codes pop-up, click Add to create as many Code values as you like, and name them. Click Close. Figure 76 – Creating activity codes
Below are the steps to assign activity codes to activities: •
Display the Columns dialogue box by right-clicking on the columns of the activity window.
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Search the activity code in the Available options area and move it to the Selected options area by double-clicking it. Hit OK.
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In the activity window, select an activity, click the cell of the activity code, and you will see a pop-up asking you to select a value, as shown in Figure 77.
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Double-click the value.
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If you want to assign the value multiple activities, you can use the Fill down command. Figure 77 – Dialogue box for selecting an activity code value
COMPARING ACTIVITY CODES AND UDFS (USER DEFINED FIELDS) AND GLOBAL CHANGE Even though UDFs (User Defined Fields) look similar to activity codes, they differ in usage – an activity code has a code value used in grouping and filtering activities, while a UDF has no code value, as shown in Figure 78. UDF is generally used for taking a note or recording data temporarily while using Global change. Figure 78 – Activity code and UDF
Global change is commend allowing P6 users to make batch changes to activities and their attributes, including durations, activity codes, expenses and more. Below are data types that are commonly used in schedule management and can be changed with Global change: •
Activity area – Activity ID and name, activity type, duration type, percent complete type, and WBS.
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Duration and date area – Original and remaining duration, calendar, expected finish, primary constraint and constraint date, and secondary constraint and constraint date.
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Progress area – actual start and finish, duration % complete, physical % complete, and units % complete.
HANDY TIP – AN EASY WAY TO CHANGE THE ORDER OF
COLUMNS IN AN ACTIVITIES TABLE You can click and drag any column that you want to move.
Refining the schedule Refining the schedule means optimising the project schedule by reviewing network logic and removing constraints on the working space or resources, as well as performing what-if scenarios as necessary. In this stage, schedulers will experience a lot of repetitive work – scheduling and adjusting – to find the optimised project schedule. In this phase, the level of experience and knowledge of each scheduler will be revealed. The quality of the project schedule is dependent on this stage. Before you begin refining your project, you need to preserve the original in case you end up needing to go back. •
Create a copy of your project and re-name the copy as suggested in the preparation chapter: Project name + “Backup” + “Analyse” + date.
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Reschedule the copy: many calculated fields and log files will be updated.
CHECK THE BASICS Prior to scheduling, you need to review all relevant documents: The Contract Agreement, the Project Charter (if any), the Project Management Plan, guidelines for schedule management (if any), the approved Work Estimate, and any work scope-related documents, drawings, specifications, etc. Go through each document and tag on any page that has schedule-related information or requirements. •
Check whether the WBS of the schedule covers all of the work scope.
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Check four key dates in Primavera P6 and confirm that they are set in the Dates tab of the Projects window (see Figure 79) – Planned start date (project start date), Planned finish date, Must finish by date, and Data date. The Planned finish date should fall on or before the Must finish by date so that activities do not have negative float. When the project is still in the planning phase, the DD should not exceed the Planned start date. Figure 79 – Dates tab of the Projects window
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Activity types have to be reviewed. Normal tasks should be of the task-dependent type.
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Calendars seriously affect project duration; thus, schedulers should make sure that each calendar has proper non-working days and working hours/day, and each activity is assigned to the proper calendar.
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Generally speaking, only the start and finish milestone activities are allowed to have an open-ended relationship. Fix other activities with open-ended relationships by linking them with other activities, if possible.
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Does your client allow the schedule to have leads or lags? If not, get rid of them. You can find them by using the P6 Report Wizard. Finding lags using the Report Wizard is discussed in another chapter.
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Check constraints in the schedule. Are they all allowed by your clients? If so, record reasons in UDFs.
SCHEDULING Scheduling aims to determine whether or not the draft schedule to meet the project completion. Current DD and Schedule options. Current DD should not exceed the project start date. Figure 80 – Schedule dialogue box
Before scheduling, users must set some options in the Schedule option dialogue box. To view the Schedule option dialogue box, click the Options button in the Schedule dialogue box. •
Ignore relationships to and from other projects – This determines whether Primavera P6 will take into account logic relationships between the active project and any other projects while scheduling. This relates to the ability of P6 to have logic links between multiple projects.
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Make open-ended activities critical – This determines whether the software will show activities without successor relationships as critical.
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Use expected finish dates – This determines whether P6 is accounting for expected finish dates.
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Schedule automatically when a change affects dates – This determines whether P6 will recalculate the schedule automatically whenever any date is changed.
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Level resources during scheduling – This determines whether resources will be
levelled while scheduling. •
Recalculate assignment costs after scheduling – This determines whether assigned costs will be recalculated after scheduling.
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When scheduling progressed activities use – This determines whether the schedule is calculated using retained logic, progress override, or actual dates. This is related to processing out-of-sequence activities. The retained logic setting means that if an activity starts out of sequence, the remaining duration of that activity will be delayed until all of its predecessors have finished. This option can affect the project duration in updating the schedule; therefore, some clients define this option in their requirements related to schedule management. Details are introduced in another chapter.
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Calculate start-to-start lag from – This determines how SS relationship lag is calculated. The early start setting means that the amount of lag is dependent on the early start date of its predecessor.
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Define critical activities as – This determines whether the software is calculating critical activities as the longest path, or as a function of a certain value of total float.
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Calculate float based on finish date of – This determines how P6 will take into account multiple projects linked together.
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Compute total float as – This determines how total float is calculated.
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Calendar for scheduling relationship lag – This determines how P6 will calculate relationship lag. Since a lag is assigned to a relationship, users have to choose one of the options. A lag is created because of a successor activity; therefore, the successor is responsible for the lag.
“Calculate multiple float paths” in the advanced option is to determine how P6 will trace multiple logical paths to specified activities.
SCHEDULE LOG REVIEW The schedule log shows key schedule-related statistics. The schedule log is a text file that can be generated automatically while scheduling. You can view it by hitting View log in the Schedule dialogue box (see Figure 81). Figure 81 – Sample schedule log
Scheduling/levelling settings show the settings for schedule options. Statistics (Among statistics, data of activities, not started, in progress, and completed can be used as information in the regular report.) •
Projects – Shows how many projects were scheduled using P6.
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Activities – Defines the total number of activities in the schedule.
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Not started – Shows the number of activities that have not yet started.
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In progress – Shows the number of activities in progress.
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Completed – Defines the number of activities completed.
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Relationships – Provides the total number of relationships used in the schedule.
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Activities with constraint – Provides a count of the total number of activities with constraints.
Warnings (Data of warning is used in analysing a schedule) •
Activities without predecessors – Shows the number of activities that lack predecessors.
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Activities without successors – Shows the number of activities that lack successors.
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Out-of-sequence activities – Shows the number of activities that have started before their predecessor activity has finished.
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Activities with actual dates > data date – Shows the number of activities that have actual dates later than the DD.
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Milestone activities with invalid relationships – Checks the legitimacy of logic relationships to milestone activities.
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Finish milestone and predecessors have different calendars – Shows whether finish milestones and their predecessors have different calendars.
Scheduling/levelling results •
Projects scheduled/levelled – Relates to how many projects were scheduled.
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Activities scheduled/levelled – Provides the number of activities scheduled.
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Relationships with other projects – Shows relationships by which activities are linked with the activities in other projects.
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Data date – Show the data date.
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Earliest early start date – Shows the earliest early start date in the project after calculation.
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Latest early finish date – Shows the latest early finish date in the project.
FINDING MISSING RELATIONSHIPS The most difficult aspect of developing a schedule is probably accurately linking activities with each other with appropriate relationships, without omitting. Incorrect relationships can easily distort total float, resulting in an incorrect project duration. To develop a proper project schedule, schedulers have to prepare network diagram of work package level in advance. An ex post facto method is to draw a graphical summary schedule that will be used in checking the omission and failure of network logic. Figure 82 shows an example of a graphical summary schedule for a railway project. The horizontal orange lines are permanent ways work (track), and the vertical rectangles represent civil works (earth work, viaducts, and tunnels). Track work cannot start before all civil works are completed; thus, all civil works should lie under track work in the schedule. If any relationship is missing between civil work and track work, track work will start before the civil work in that section is finished. This summary schedule is prepared on the basis of the draft schedule, and its graphical icons help to clarify the schedule and check activity dates. Figure 82 – Example of a graphical summary schedule
SPATIAL CONSTRAINTS REVIEW
Sometimes work interferences occur between disciplines in a small work space. Schedulers can find these types of constraints by grouping activities that will be performed at the same time and place. Figure 83 shows an example of grouping by floor. To do this review, follow these steps: •
Identify the areas, spaces, floors, and rooms that are expected to be crowded by different subcontractors.
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Create activity codes and assign them to activities according to location, such as floors, rooms, and areas.
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Reorganise activities in accordance with activity codes by using “Group and Sort”.
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Review Gantt charts at each area, space, floor, and room. If there is any place where multiple tasks will be performed at the same time and it is expected to be crowded with different subcontractors, link the activities with Finish to Start relationship to prevent overcrowding. Figure 83 – Grouping by Floor (third floor)
INTENTIONAL DELAY On railway construction projects, some infrastructure or facilities do not need to be completed early. Railway construction projects usually have long construction durations; the buildings and facilities of depots (which are used to keep and maintain trains) used to be completed one year prior to opening, even though they have no successor tasks. In terms of economics, the plan should be rescheduled to reduce the project cost. Depots tend to have sizable infrastructure requiring huge budgets; thus, if a depot is finished one year early, its interest cost for one year cannot be ignored, and its buildings and facilities will be maintained unnecessarily until opening, increasing the project cost.
LEVELLING RESOURCES
Levelling resources is a technique by which the start and finish dates of activities are adjusted on the basis of resource constraints (or resources limitations). The purpose of levelling resources is to balance the demand for resources with the available supply. There are some cases in which multiple activities requiring the same resources, such as machines, are performed at the same time, causing a resource shortage. The tasks should be rescheduled to resolve the resource shortage to adjust resource usage profile. Figure 84 shows the usage profile of plasterers (R-10); the black line represents the maximum units per time, and the red bars represent over-allocation. Figure 84 – Resource usage profile
Even though levelling resources is a useful feature in Primavera P6, its use is not recommended because levelling resources sometimes generates unintentional changes in the schedule. Actually, Primavera P6 processes resource levelling by moving schedule tasks mechanically, not only for solving resource constraints but also for achieving a more consistent level of resources throughout the schedule duration. Since levelling resources is not controllable, P6 operators prefer to adjust activity dates manually. The following steps are for manual resource levelling: •
Display columns of Free float and Total float to view.
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Go to Resource Usage Profile view and check any over-allocated resources.
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Adjust the activities, beginning with those with a large Free float, by adding relationships or lags.
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If you have finished adjusting the activities with free float and there are still overallocated resources, adjust the activities with a large Total float first.
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If you have finished adjusting the activities with Total float and there are still overallocated resources, see if there is any room to change the schedule without modifying the completion date of the project.
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All activities moved due to levelling resources should be recorded in order to be reviewed when developing the recovery plans.
WHAT-IF SCENARIOS
To find the optimised schedule, schedulers develop various what-if scenarios in the planning phase, which can also be used in catch-up planning. The optimised schedule reflects the working environment and resource management strategy. So what is a scenario? A scenario involves a question and an answer. Here are some examples of questions for scenarios: •
How many people per day will be needed to complete this activity in three weeks?
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If we increase work time from 10-hour to 12-hour shifts, how much time will we save?
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The budget for this task is $20,000. How quickly can it be done with six men per day?
To optimise duration and performance, activities should be assigned with resources, and the duration type should be “Fixed units”. •
Go to the Projects window and select the project for which you want to create what-if scenarios.
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Right-click, and click “Create Reflection” in the popup menu.
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You will see a project with a question mark (?) at the project icon, and its project name has “Reflection” additionally. Figure 85 – Preview dialogue box for merging changes
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Open the project, find critical activities, and change its units/time.
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You can see changes of duration when you change the units/time of critical activities as well as the project duration.
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If you have built the optimised schedule, right-click, and click “Merge Reflection into Source project”.
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You will have a dialogue box (see Figure 85) in which to review changes to the project. Select the activities to merge them with the original project.
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Hit “Merge Changes” to apply.
Analysing the schedule The schedule development phase and the analysis phase are not separated when establishing a schedule. A scheduler should repeat the cycle of developing, analysing, and revising a project schedule alternately in order to produce a robust and detailed schedule. Participants in a construction project will encounter unfamiliar environments; thus, a schedule needs to reflect as many risks as possible by repeating schedule development cycle.
DEFINING CRITICAL ACTIVITIES Do you know the difference between the critical paths revealed by “Total float less than or equal to” and “Longest path” in the scheduling options box? The critical path presented by “Total float less than or equal to” is determined on the basis of total float. If the option has one day, any activities that have total float less than or equal to one will be critical activities. As for the “Longest path” option, the chain of activities that has the longest duration will be the critical path. In a simple schedule, you will find that both options present the same number of critical activities while different numbers of critical activities in a big schedule. Sometimes we feel like comparing the two. Here are the steps: •
Go to the editing dialogue box for columns in the activity table.
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Search for one called “Critical” and another called “Longest path”.
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Add them to the Selected options area.
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You may see that the longest path has more activities than does the critical path with zero (0) total float.
Points you have to review for the critical path: •
Compare the critical path revealed by scheduling with the critical path you expected.
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Check whether any activity on the critical path has unnecessary or incorrect relationships or lag.
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Check whether any relationships are missing for the critical activities.
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Check whether the critical activities have proper durations and calendars.
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Check whether any critical activity has constraints.
CRITICAL PATH AND NEAR-CRITICAL PATH In the executing phase, any activity path can become the critical path due to a delay of the activities on the non-critical path; thus, the scheduler should monitor near-critical paths, too. You can draw critical paths and near-critical paths with scheduling in Primavera P6. To filter near-critical activities, you can use float path and float order. Float path demonstrates the order of a group of total float value; the lower the number, the lower the
amount of floats; thus, a float path with number 1 is the critical path. Float order is the sequence of the activity relationships in the same float path, as shown in Figure 86. Float path and float path order provide powerful features to analyse the critical path and nearcritical path. Figure 86 – Float path and Float path order
You can organise the critical path and near-critical paths in different ways without changing any data, if you follow these steps: •
Go to the Group and sort dialogue box, delete WBS in Group by column, and click OK.
•
Filter only the last activity (the project completion activity) with “Activity ID” for “Parameter” and “equals” for “Is”, and click OK. You will see only the activity in the Gantt chart window.
•
Go to the Relationships tab and select the activity’s predecessor that drives the dates of successors. If you do not see the Driving column in the Successors section, you can display it by customising columns.
•
Hit the “GoTo” button below and you will see the activity you selected. Select the activity that appears, and then repeat displaying other activities by using the “GoTo” button.
•
When completing displaying all activity you want in the Gantt chart window, sort activities by clicking the Start column. You may need to create a UDF to record these orders. If you use Activity network view, it will give you a beautiful graphic view.
HANDY TIP GRAPHICALLY
–
SHOWING
NEAR-CRITICAL
ACTIVITIES
Critical activities are usually shown red in the bar area, but near-critical activities are not. Use these steps to show near-critical activities in other colours: •
Go to the Filters dialogue box and create a new filter by clicking Add.
•
Name it (e.g., “TF 1–3”) and click Modify.
•
Choose “Total float” for Parameter and “within range of” for Is.
•
Input “1d” in the Value column and “3d” in the High value column.
•
Save it by hitting OK, and close the Filters dialog box.
•
Go to the Bars dialogue box and create a new bar by hitting Add.
•
Name it (e.g., “TF 1–3”), and select “Remain Bar” for Time scale.
•
Choose “TF 1-3” in the filter column.
•
Select the bar type and colour at the Bar style below.
•
Make sure “Display” for the new filter is checked and save it by hitting OK.
You will see that activities with a total float of 1 to 3 have the bar type and colour you have set. You can also make more near-critical bars, such as “TF 4–6”. If you want to show near-critical activities graphically in the activity table, follow the steps below: •
Go to the UDF dialogue box and create a new UDF.
•
Name it “TF 1–3” and close the dialogue box.
•
Display the column you create in the activity table.
•
Go to the Global change dialogue box and create a new change.
•
Click Modify, and select “Total float” for Parameter and “within range of” for Is.
•
Input “1d” in the Value column and “3d” in the High value column.
•
In the section named “Then”, choose the Critical indicator for Parameter, “=” for Is, and “Green” for the Parameter/Value column.
•
Save it by hitting OK, and run the Global change you have made.
•
You will see the Global change report. Review it and, if everything is OK, hit Commit changes.
You will see green indicators in the UDF column “TF 1–3” in the activity table.
RISKS ANALYSIS In terms of schedule management, all activity delays can be risks. Schedule risks that impact schedule duration include design issues (design changes and design errors), fluctuating resources, resource experience, etc. However, not all issues have the same impact on the schedule: •
A delay of the activities on the critical path has a stronger impact on the schedule than that of other activities which have positive total floats. The activities having positive
total floats can be delayed within the range of total floats, causing no delay of a project completion date. •
A delay of the activities lying on the front of the critical path has a stronger impact on the schedule than that of activities lying on the back of the critical path because the former has more successors than the latter.
•
A delay of the activities with numerous successors has a stronger impact on the schedule than that of activities with a sole successor.
Unfortunately, schedulers cannot analyse the impact of each activity’s delay (risks) quantitatively with Primavera P6. Instead, you can analyse schedule-related risks with Primavera Risk Analysis, which provides four powerful analysis functions, as follows (Figure 87 illustrates the relationships between factors and analysis): Figure 87 – Relations between analyses
•
Duration Sensitivity – computes the correlation between the duration of each activity and that of the entire schedule, using Pearson’s product moment. If an activity ranks high in this calculation, delay of the activity will highly affect the project completion.
•
Criticality Index – the proportion of the iterations in which an activity was on the critical path. If an activity ranks high in this analysis, the activity will likely become a critical activity.
•
Duration Cruciality – calculated by multiplying its duration sensitivity by criticality index.
•
Schedule Sensitivity Index – computed by multiplying its criticality index by the ratio of its variance against the variance of the whole schedule. Variance means standard deviation ([pessimistic duration – optimistic duration] / 6).
HANDY TIP – FINDING LAG You can see most schedule-related data in the database of Primavera P6 by customising the columns of each window; however, some are not visible, such as lag. If you want to see lag, you have to review the activities one by one, which can take a long time. To easily
find the lag of an activity using Report Wizard: •
Open the project for which you want to find lag.
•
Go to the Reports window (Tools – Reports – Reports) and select the report (AD-02 Activity Relationships). Primavera P6 PPM (version 15.1) has the report.
•
Run Report Wizard (Tools menu), and you will see the Report Wizard dialogue box (“Modify Wizard Report” will be checked). Hit Next.
•
You will see a second dialogue box. If there is no “Activity relationships” in the section “Selected Subject Areas”, bring it from the section “Available Subject Areas”. Click Next.
•
When you see the third dialogue box, hit the Columns button and bring lag from the Available options section to the Selected options section, as shown in Figure 88. Hit OK.
•
In the Report title dialogue box, create a name and hit Next.
•
If you can see the Report generated dialogue box, hit the Run report button.
•
You will see the Run report dialogue box. Hit OK.
•
You will see the lag of activities in the report. Figure 88 – Report Wizard and the columns dialogue box
REMAINING EARLY COST CURVE AND PAYMENT CURVE Figure 89 shows an example of a remaining early cost curve and payment curve. Contractors use remaining early cost curves to calculate budgets and anticipate workloads over the project period, while clients use payment curves to calculate the funds to secure over the project period. Figure 89 – Early cost curve and payment curve
The two curves do not synchronise because the client pays the contractor the advance payment (284) at the beginning of the project (Month 1), and deducts part of the advance payment and retention from every payment; invoice processing takes time, as well. To make a payment curve, schedulers should manipulate the remaining late cost data in Excel. •
Go to the Resource assignments window in Primavera P6 and set up Spreadsheet fields to display remaining early cost.
•
Change the timescale according to the time units of the graph.
•
Select all the remaining early cost data and copy and paste it into Excel.
•
Sum up the cost over the period in Excel.
•
Go back to the Resource assignments window and set up Spreadsheet fields to display remaining late cost.
•
Select all the remaining late cost data and copy and paste it into another Excel sheet.
•
Sum up the cost over the period.
•
Define the total amount of the advance payment and retention, if any, and put it in Month 0 (at the beginning of the period).
•
Deduct part of the total amount of the advance payment and retention from the monthly remaining late cost.
•
Combine both summaries into a table, make cumulative date by adding values, and draw a graph based on the table.
ORGANISING MILESTONES The bigger the project, the greater the number of activities. On a big project, it may be difficult to identify milestones, which are usually important activities for estimating project progress. It will usually be most efficient to group milestones and put them at the top of the schedule, as shown in Figure 90. There are some contracts that suggest to pay based on the actualised milestones. In that case, grouping milestones will help the client and contractor communicate smoothly.
Figure 90 – Milestones
CHECKLIST BEFORE SUBMITTING SCHEDULE TO CLIENT IN THE PLANNING PHASE Schedule management •
What are the requirements related to schedule management?
•
Have the requirements been defined by reliable documents (e.g., contract agreement and contractual documents, international standard codes, etc.)?
Work scope •
Has the work scope been defined by reliable documents?
•
Has WBS been reviewed by participants (e.g., departments, field site offices, subcontractors, suppliers, etc.)?
•
Do the work packages cover all the work scope and all requirements of the client?
•
Have all work packages been assigned to responsible teams or organisations (e.g., departments, field site offices, subcontractors, suppliers, etc.)?
Schedule •
Does the end date of the schedule meet the completion date of the project?
•
Do activities follow the standard activity ID and name structure?
•
Has the schedule been created based on schedule-related requirements?
•
What is the basis for activity durations and relationships?
•
Have constraints and lag/lead of activities been recorded?
•
Have resource allocations been reviewed to prevent over-allocation?
•
What are the milestone activities in the schedule?
•
What are the critical and near-critical activities in the schedule?
•
What are the schedule-related risks in the schedule?
UPDATING, ANALYSING AND REPORTING
Methodologies and processes of progress updating After a project baseline (planned schedule) is published, engineers in departments and site offices carry out their tasks according to the project baseline and update the progress status. The main purposes of progress updating are to (1) understand the project status, (2) anticipate the finish date of the project by computing performance, and (3) calculate the payment. When updating the project schedule, it is necessary to define progress based on as-built schedule information, such as daily field reports, project meetings, progress photographs, etc. Progress can be defined by schedulers, department staff, counterparts at field site offices, or subcontractors. When defining progress, relevant documents, photos, and records should be procured as evidence.
DATA TO MAINTAIN IN THE IMPLEMENTING PHASE Primavera P6 has many kinds of data, so it is no exaggeration to say that schedule management is P6 database management. Schedulers should understand data types and their relations with other data. To analyse and maintain progress data, schedulers should know controllable data from uncontrollable data. Figure 91 illustrates the relationships between progress data. As the diagram shows, controllable data are Original duration, Remaining duration, Actual labour units, Actual non-labour units, Remaining labour units, and Remaining non-labour units. Note that once an activity has started (its start date has been actualised), you can change its finish date, not by changing the original duration, but by changing the remaining duration or At completion duration. Original duration is used only for computing Duration % complete. In other words, once an activity has started, original duration becomes planned duration, which is the basis for calculating Duration % complete. Figure 91 – Relationships between schedule progress data
Primavera P6 (version 8.3) has 671 data types; however, users do not need to understand all of them because P6 has been developed for various types of projects to support various
users. Figure 92 shows recommendable data types and names for P6 operators to understand and monitor in the updating phase. Figure 92 – Data types to monitor in the updating phase
COMMUNICATION TYPES FOR COLLECTING PROGRESS DATA Progress and as-built information will be gathered to reflect actual progress as of the DD or contractor’s monthly progress payment estimate date. There are several types of methods for communication between counterparts and schedulers to transmit progress data: •
Using a network version of Primavera P6 (EPPM) – P6 EPPM gives the project team anytime, anywhere access to their project information through web-based user interfaces. It also provides various interfaces such as PC (or tablet), iOS, Android, and email.
•
Sharing a Primavera P6 (PPM) database – If counterparts at departments, field site offices, and subcontractors can access the Primavera P6 database using a network, they can update the project schedule directly.
•
Submitting progress data in XER format – “.xer” is a file format created from the database of Primavera P6. Engineers can submit it by email or other media to a scheduler, who then imports it into his or her own Primavera P6 database.
•
Submitting progress data in Excel format – If engineers (departments and site offices) do not have the P6 application, they may use Excel to update their activities.
•
Using network solutions (3rd party applications) – A project management team can develop their own progress management solution or customise a SAP application for progress management.
•
Other types – On smaller projects, a project team can use phone, email or other media to update schedules and communicate.
To share information conveniently, many people use cloud services, which are designed to provide easy access to applications, resources and services, and are fully managed by a cloud services provider. Examples of cloud services include online data storage and backup solutions, Web-based document collaboration services, and more.
Figure 93 – Structure of sharing files using cloud services
COLLECTING PROGRESS DATA BY MEANS OF XER FILES Collecting progress data by transmitting XER files is a classic method among P6 users. Figure 94 shows the process of updating a schedule using reflection files (XER files). •
A scheduler on a project management team makes reflection files for counterparts with different name based on naming standard if any.
•
Using filter, a layout for each counterpart should be created to help them focus on their own activities when updating. Figure 94 – Schedule updating using reflection files
•
The scheduler exports the reflection files in XER format and distributes them to counterparts at departments, field site offices, and subcontractors.
•
Counterparts update the schedule (reflection file) based on actual performances and send it back to the scheduler.
•
The scheduler imports the XER file into the Primavera P6 database and converts the schedule into a reflection.
•
He or she then analyses the updated schedule by comparing it with the original schedule prior to merging it into the source schedule. If there are any unsatisfied updates in the reflection schedule, he or she can ask the counterpart about it.
•
If the updated schedule is OK, the scheduler can merge it into the source schedule.
There may be a problem when importing XER files from other users (subcontractors or staff of field sites). Their global data comes along for the ride – any calendars, resources, codes, etc. used in a project go with the project when it is exported and may end up polluting your P6 database when you import an XER file they have sent you.
HANDY TIP – IMPORTING A HIGHER VERSION XER FILE What if a counterpart has sent you a higher version “.xer” file than your Primavera P6 can import? There are two solutions to this problem. The first is to call the counterpart and ask him or her to save it as a lower version that your P6 can process, and send it again. The second is to change it yourself, as follows: •
Open the XER file in Windows Notepad.
•
You will see the version of Primavera P6 on the very first line, for example, “ERMHDR 15.1” (see Figure 95).
•
Edit the number in the line to match the version of P6 installed on your computer.
•
Save it without changing the file extension.
•
Import the file into Primavera P6 as usual.
(This “fix” is not guaranteed to work every time because there may be version differences that will no longer be handled properly, but results are most often favourable.) Figure 95 – XER file opened in Windows Notepad
You may be wondering how this works. An XER file is a simple database file with Tab as a delimiter. Thus, you can open and modify it in any text editor or program that can read a text file, including Excel: Open a new sheet in Excel, and then go to data menu. You will see “From text”. Click it and then select the XER file. You will see a pop-up asking you to choose the file type. Select “Delimited” and hit Next. In the second dialogue box, if “Tab” is selected, click Next and hit Finish in the third pop-up. You will see XER data in the sheet.
COLLECTING PROGRESS DATA BY MEANS OF AN EXCEL FILE If field site offices and subcontractors have no Primavera P6 package, a scheduler who needs to centrally collect all schedule-related data from them should use Excel files as
follows: •
Export the Excel file from P6 and modify it for data collecting, as shown in Figure 96, and then distribute it to them.
•
Excel files are updated by counterparts at site offices and subcontractors.
•
Gather updated Excel files.
•
There are two ways to import data in Excel to P6 – modifying the format of the collected files to import into a Reflection schedule in P6, or typing the progress data into a Reflection schedule manually.
•
Reschedule the Reflection schedule. If you find any problems when comparing it with the original, for example, delay of activity, contact counterparts to fix the problem.
•
When all problems with the Reflection have been fixed, merge it with the original schedule. Figure 96 – Example of Excel format for progress data collection
COLLECTING PROGRESS DATA BY MEANS OF A PROJECT MANAGEMENT INFORMATION SYSTEM If you plan to run a self-developed PMIS for schedule management, the following should be taken into account when planning, designing, developing and operating the system: •
When it comes to network systems, there are two types: client-server and web-based. The client-server system is much faster than the web-based system; however, it requires installation of the system on each personal computer, while the web-based system does not.
•
It should provide at least four types of access modes (security and privilege): super user, scheduler, counterpart, and management. Super user mode is for the system administrator who will assign security profiles to each user and manipulate planned schedule data. Scheduler mode is for the schedulers on the project management team, who will manipulate planned data and actual data. Counterpart mode is for the
counterparts at departments, field site offices, and subcontractors, who will input actual data into the system. Management mode is for the management or client who will only view the plan and actual data of the project. •
The data types processed in the system should be similar to the data types previously introduced in “Collecting progress data by means of an Excel file”.
•
The user-interface for inputting plan data should be similar to Excel’s, and the userinterface for inputting progress data should be similar Primavera P6’s. User-interface should not require much training of its users.
•
Manuals should be prepared for system maintenance, input of plan data, input of actual data, data maintenance, etc.
Below is the process for running PMIS: (1) Establishing a plan – A scheduler exports the approved project baseline in Excel format from Primavera P6 and inserts Excel data into the PMIS as a plan. (2) Opening the system – A super user opens the system to let the counterparts input actual data. (3) Updating the schedule – The counterparts input progress data into the system. (4) Closing the system – After inputting all actual data, a super user closes the system. Counterparts will not be able to change any data while schedulers at the project management team analyse the project schedule. (5) Analysing progress – The scheduler exports progress data from the system, updates the project schedule, and analyses it. If a problem is found with the updated schedule, counterparts should be contacted. (6) Updating baseline or actual data – If a master schedule is changed or actual data in the system needs to be fixed, data should be changed. (7) Repeat (1)–(6) at the next updating period.
Updating the schedule When updating the schedule, schedulers should make a copy of the current project schedule. This is to ensure that each and every update has a unique schedule file associated with it.
PRIOR TO UPDATING PROGRESS IN PRIMAVERA P6 If you have finished gathering information and data related to project progress, use Filter for the activities that have not started or are in progress, as shown in Figure 97. Figure 97 – Filter setting
If you want to narrow down the range of activities in terms of start and finish date on the basis of DD, you can use another filter option. Figure 98 shows a filtering set to narrow down the activities for monthly progress updates. DD in the Value column means DD (the latest update date). Figure 98 – Filtering activities
PROGRESS UPDATING FOR EACH TYPE OF ACTIVITY There are three items (duration, physical, and units) related to progress updating in P6, and each manner of updating is slightly different. The following steps are for the activities assigned with Physical for percent complete type (see Figure 99): (1) Check “Started” (or “Finished” if the activity is in progress), and then select the date. Any date can be actualised, even if the date is a non-work date. (2) Update remaining duration. Do not make changes to “At completion”, which will be updated automatically based on the original and remaining durations. (3) Go to the Step tab and check completed step(s), or update percent of step(s). If there
is no step there, you can update Physical % in the Status tab. The value of Physical will affect that of Earned Value Cost (B). (4) Go to the Resource tab and update actual and remaining units. The value of Units will affect that of Actual Cost (C). Figure 99 – Statusing for Physical type
When updating activities, using Expected finish date is sometimes preferable to entering remaining duration for the activities that are not completed. P6 operators frequently make a mistake when inputting remaining days because of non-working days. Therefore, many P6 users prefer using Expected finish date. To use this, P6 users have to check whether “Use Expected Finish Dates” is activated. The following steps are for the activities assigned with Duration for percent complete type (see Figure 100): (1) Check “Started” (or “Finished” if the activity is in progress), and then select the date. (2) Update remaining duration. Do not change “At completion”, which will be updated automatically based on the original and remaining durations. Remaining duration is linked with Duration %; thus, you do not need to update the percentage. The value of Duration % will affect that of Earned Value Cost (B) because it is linked with Activity complete type. (3) Go to the Resource tab and update actual and remaining units. The value of Units will affect that of Actual Cost (C). Figure 100 – Statusing for Duration type
The following steps are for the activities assigned with Units for percent complete type (see Figure 101): (1) Check “Started” (or “Finished” if the activity is in progress), and then select the date. (2) Update remaining duration. Do not change “At completion”, which will be updated automatically based on the original and remaining durations. (3) Go to the Resource tab and update actual and remaining units. The value of Units will affect those of Earned Value Cost (B) and Actual Cost (C). Figure 101 – Statusing for Units type
If you want to input actual overtime units (actual overtime cost), follow the steps below: •
Go to the resources window and select any resources except Material type resources.
•
Hit the Details tab, check “Overtime Allowed” and enter a value in the Overtime factor. The overtime factor must be between 0.0 and 10.0.
•
Then go to the Resources tab of the Activities window and display three columns called “Overtime Allowed”, “Actual overtime units” and “Actual overtime cost” by customising columns.
•
Enter values in Actual regular units, as desired. Actual overtime cost will be computed as Actual overtime units multiplied by cost per time (“Price / Unit”) multiplied by Overtime factor. And Actual cost will be calculated as Actual regular cost plus Actual overtime cost.
If you want to view the relationships between Overtime cost and regular cost, display two more columns called “Actual Regular Units” and “Actual Regular Cost”.
SUMMARISING AND STORING PERIOD PERFORMANCE Performance data in the Activity usage spreadsheet is not actual progress data, it is just the distributed total values of actual performance over the period. Therefore, you need to save progress data regularly into the predefined financial period. To store actual performance after updating the schedule, create financial periods, as follows: Figure 102 – Financial periods dialogue box
•
Open the financial periods dialogue box, select a start date, and then click Add to create.
•
If you want to create multiple financial periods at the same time (see Figure 102), follow the steps below:
(1) Choose the start date of the financial period. (2) Select the end date of the financial period. (3) Define the interval of the financial period. (4) Click Batch create to create. (5) You will see the financial periods you have just created. •
Open the Store period performance dialogue box (Tool menu), and then click Financial period.
•
Select a financial period and hit Store new to save performance. Figure 103 – Storing performance
HANDY TIP – UPDATING PROGRESS (EV) USING ACTIVITY % COMPLETE Prior to following this tip, you must check that Activity % complete is selected in the option “Technique for computing performance percent complete” of the Earned Value tab under Admin preferences in the Admin menu. Note that only the activities that are in progress (have the actualised start date) can be updated, and any activity that has Steps cannot be updated. Display the Activity % complete column in the activity table, and then input progress data as needed. That’s it! If an activity’s Percent complete type is Physical, its values of Physical and Activity % complete will be synchronised. Note that the remaining duration of a Duration type activity is affected by the value of the Activity % complete. Also, when updating a Unit type activity, only the remaining units of resources are changed. In other words, if a Unit type activity has 30 actual units and 70 remaining units, indicating 30%, when you update it from 30% to 50%, the remaining units will be 30. To conclude, updating the Activity % complete requires many conditions that often do not work as we would like, so it is not recommended.
SETTING THE DATA DATE When scheduling, you need to be careful in setting the DD. The DD hour has to be set later than the working hours in the assigned calendar, for example, 10 p.m. Schedulers sometimes make the mistake of skipping the hour setting of the DD; its default hour is 0 a.m., as shown in Figure 104. What if you have assigned an activity in P6 to be finished at 4 p.m. on 31 March and you are scheduling as of 31 March with a default hour of 0 a.m.?
Its successor activity that is scheduled to start 1 April will be shown as starting 31 March. Figure 104 – Setting the Data date
Note that DD setting affects your project. The start dates of all activities that have not started (their start dates have not been actualised) will be delayed to the DD, and the finish dates of all activities that have not finished (their finish dates have not been actualised) will be the DD plus the remaining duration.
TECHNIQUE FOR COMPUTING PERFORMANCE PERCENT COMPLETE If EV does not equal what you expect after updating the project progress, check the option “Technique for computing performance percent complete” of EV (Admin – Admin Preferences), as shown in Figure 105. Figure 105 – Earned value options
There are six options. Among them, Activity % complete, 50/50 % complete, and 0/100 % complete are commonly used in defining progress. Activity % complete is the default
option, and it reflects the progress of activities whenever updated. On the other hand, the 0/100 % complete option reflects progress only when an activity is completed. Any percent complete will represent zero (0) percent progress until the activity is completed. In the case of 50/50 % percent, once an activity has started (actualised), the tasks is marked as 50% completed, and when it is completed, the progress will be 100%. Figure 106 illustrates comparisons between the accumulation of real project progress and that of measured progress in Primavera P6 for each option. In the case of Activity % complete, measured progress equals real project progress at every DD when project progress is updated. In the case of 0/100 % complete, the measured progress never equals the real progress except when the project is completed (all activities are completed). When it comes to 50/50%, although the measured progress exceeds the real progress, it is reasonable because its excess compensates for the undervalued progress between DDs. Figure 106 – Comparison of real progress and measured progress for each option
On the other hand, applying progress measurement varies based on task type. Below are examples of progress measurement method assigned to activities in a project: •
Engineering tasks (e.g., design, feasibility study) – 0:100 % complete.
•
Procurement tasks – Issues for procurement order (20%), manufacturing and shipping (40%), delivery (20%).
•
Construction – Activity % complete.
HANDY TIP – COMPUTING THE WORKLOAD OF SCHEDULE UPDATING Below are the steps to calculate the workload for schedule updating: •
Copy the master schedule and delete units assigned to resources of activities by using “Top-down Estimation”.
•
Create a resource with $1/d price.
•
Assign as many units as original duration to each activity using Global change.
•
Display Activity usage profile view at the bottom of the Activities window and adjust the time scale as desired.
•
At the top of the Activity usage profile view, you will find the total budget of the project based on the time scale.
THE REASONS WHY ACTUAL COST SHOULD BE UPDATED As you can see in Figure 107, the client does not need to know the status of AC, which comes from the value of Units in P6 under the Fixed-price-contract type; however, schedulers should update it. Why? Figure 107 – Relationships between EVM values and other data
•
Some contract agreements have a condition stating that when the contract is terminated, AC will be the basis for payment. This is not a good condition for contractors because AC is generally smaller than EV.
•
In the case of Force Majeure, compensation can be calculated on the basis of AC.
•
Projects that do not allow for time to calculate exact quantities, such as disaster recovery projects, will have a Cost-reimbursement type contract, in which AC is used to compute payment.
•
The client (actually, the supervisor) requires to analyse productivity for a contractor’s work performance to increase performance in advance.
•
In the case of an in-house project, AC is the most important factor by which to analyse productivity. Productivity can be defined as the ratio of output to all of the resources used to produce that output.
Analysing progress Progress analysis aims to find any problems in implementing the project, and prepare countermeasures. Analysing progress involves comparing the updated schedule with the baseline. To compare them, P6 users have to create the project baseline and assign it to the updated schedule. You will see two types of baselines in Primavera P6: Project baseline and User baseline. A project baseline is the baseline that is set for all users who will access that particular project, while a user baseline can be set for a current user. User baseline has three types: primary, secondary, and tertiary user. While a Primary user baseline has features that compare a project’s costs and resourcing, secondary and tertiary user baselines do not.
COMPARING SCHEDULES Claim digger, in the Tools menu, helps schedulers compare the current schedule with the updated schedule and view a detailed listing of the changes between them. It provides a means for developing a report which shows detailed information about the changes between the schedules. Schedulers should pay attention to the following: •
Changes in relationship types, especially changes from FS to SS relationships. This can indicate that departments, field site offices, or subcontractors are trying to reduce the overall planned duration of the schedule by fast-tracking the schedule.
•
Changes to the durations of remaining activities, particularly activities on the critical or near-critical path. This can indicate that departments, field site offices, or subcontractors are trying to reduce the overall planned duration of the schedule by crashing the remaining durations.
•
Changes in activity names. Changing activity names can change the perception of the scope of the work contained in an activity. Without associated changes in duration or resources, it is possible that the newly named activity no longer presents a reasonable duration for the execution of the new scope of work.
•
Added activities, especially activities which represent alleged delays. Representation of delays in an updated schedule is not appropriate until a Time impact analysis (TIA) has been submitted and accepted by the client.
•
Added constraints, particularly when they appear to fix the start of activities in the future. Activities should be driven by the logic of the schedule, not constraints.
EARNED VALUE METHOD With three values (PV, EV, and AC), Primavera P6 computes Schedule Performance Index and Cost Performance Index, etc. as follows: •
Budget at completion (BAC) – The total amount of money that you expect to spend to
complete a task or the entire project. •
Schedule variance (SV) – The difference between EV and PV (SV = EV – PV). It is a number that tracks how long you thought a task would take during planning versus how long it actually took, and how that affects costs you are spending.
•
Schedule performance index (SPI) – Ratio of EV and PV (SPI = EV / PV). It allows you to take a closer look at the overall schedule efficiency of a project.
•
Cost variance (CV) – The difference between EV and AC (CV = EV – AC). It allows you to see the discrepancy between the amount of value that you earned on a task and the AC it required to perform. You can see the value in the column called “Accounting variance”.
•
Cost performance index (CPI) – The ratio of EV and AC (CPI = EV / AC). It lets you look at how well that money is being utilised, and provides an instantaneous check on cost performance at any point in the project.
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Estimate at completion (EAC) – The ratio of BAC and CPI (EAC = BAC / CPI). It allows you to estimate the total cost of a project as of the DD, taking into account the work that already done.
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Estimate to complete (ETC) – Theoretically, this is the difference between EAC and AC (ETC = EAC – AC); however, Primavera P6 provides various formulas to apply in calculating ETC, as shown in Figure 108. Figure 108 – Computing options for ETC
So, what option do schedulers have to select to compute ETC for their projects? Below are some examples schedulers should take into account: •
[ETC = EAC – AC]: when you expect that the remaining work will be done by the remaining cost.
•
[ETC = BAC – EV]: when you expect that the remaining work will be done by the remaining EV.
•
[ETC = (BAC – EV) / CPI]: when you expect that the remaining work will be done by
the remaining EV, affected by CPI. •
[ETC = (BAC – EV) / CPI x SPI]: when you expect that the remaining work will be done by the remaining EV, affected by CPI and SPI.
•
[ETC = (BAC – EV) x arbitrary number]: when you expect that the remaining work will be done by the remaining EV, affected by a factor you define. Figure 109 – EVM view
Figure 109 shows an example of EVM view. Generally speaking, clients are not interested in cost-related information; therefore, contractors hardly use this format in reports submitted to the client. Although EVM is a good technique for measuring project progress and performance, there may be cases in which exceeding progress, as measured by EVM, does not guarantee that a project will be completed before the completion date provided by the project owner. Figure 110 – Example of project progress
Figure 111 – Progress as of the Data date
Suppose a project consists of three components that need to be completed according to different budgets and durations, as shown in Figure 110, with budgets of £500m, £100m and £400m for Components A, B and C respectively. Before the beginning of the project, Component A was anticipated to have the longest duration; thus the completion date of Component A would be the designated the completion date for the whole project. As the project progresses, Components A and C are completed early, while Component B is delayed. At a certain point (DD), the progress of the project will be exceeded (SPI is 1.4), even though Component B is delayed, and the overall project will have been completed behind planned schedule.
PAYMENT CALCULATION The payment amount will be calculated on the basis of EV. If the contract includes advance payment and/or retention, a portion will be deducted from every payment, as shown in Figure 112. Figure 112 – Payment calculation
PERFORMANCE ANALYSIS There are two important considerations regarding performance analysis: It allows the contractor to view the project status correctly and increase performance to recover delayed activities; a client can require a contractor to increase performance in advance in order to prevent the contractor from abandoning the project later due to a lack of profitability. The following is an example of the process of performance analysis: A project has foundation work and its calculation in the BOQ is as follows: •
[A] Quantity of the foundation work is 10,000 CM (cubic metres)
•
[B] The total amount of man-hours for the work is 900,000 mh
•
[C] Accordingly, the planned productivity for the work is 90 mh/CM [B / A]
Performance for the work at the DD has been measured as follows: •
[D] Planned progress is 18% (1,800 CM) [A x 0.18]
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[E] Actual progress is 15% (1,500 CM) [A x 0.15]
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[F] Spent units is 160,000 mh
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[G] Actual productivity for the work is 106.7 mh/CM [F / E]
Analysis and revised productivity plans are as follows: •
[H] Actual performance factor is 0.84 [C / G]
•
[I] Coefficient to recover performance is 1.19 [1 / H]
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[J] Revised productivity plan is 107.1 mh/CM [C x I]
Forecasting is as follows: •
[K] Remaining quantity is 8,500 CM [A – E]
•
[L] Additional units to complete is 145,350 mh [(J – C) x K]
•
[M] Budgeted units at completion is 1,045,350 mh [B + L]
CONTROLLING THE REVISION NUMBER OF THE MASTER SCHEDULE After approval from client, the master schedule will be published as a schedule baseline. The published baselines should have version numbers. The version number should have three digits, and each digit should be changed as follows: •
X _ _ : when the completion date is changed.
•
_ X _ : when any milestone is changed.
•
_ _ X : when activities are changed.
Corrective actions and schedule revising ACTIVITY DELAY There are three types of activity delays – start, progress, and finish. Typically, a start delay does not come from an activity itself, but is due to the finish delay of its predecessor(s). While progress delay can be recovered by crashing, delayed finish cannot be recovered. Therefore, schedulers should concentrate on finish delays. Figure 113 – Variances of finish date
To check activity delay, P6 users must first display some columns in the activity table of the activities window: Variance – BL Project Start Date, Variance – BL Project Finish Date, Total Float, and Activity % Complete. You must first delete WBS level in the “Group and Sort” dialogue box (right-click the activity table to view) and then sort activities by clicking the “Variance – BL Project Finish Date” column of the activity table. Now you can see ascending variances of the finish date, as shown in Figure 113. Below are examples of analysis on delayed activities: •
The activities which have been delayed – all activities with minus value in variance (from C70 to C50).
•
The activities which have delayed the project deadline – all activities with negative total float (S10, G20, and G40). Completed (finish date is actualised) activities have no total float.
•
The activities which can be recovered – all activities that have not been actualised (C70, S10, C30, and G40, with G20 being a milestone activity).
•
The activities which should be recovered to prevent delay of the project deadline – all activities that have a zero (0) or negative value in total float whose finish dates have not been actualised (S10 and G40, with G20 being a milestone activity).
If you want to check the project progress, you can use the Progress line. To turn on the
progress line, select it from the View menu, and you will see a red line around the DD line, as shown in Figure 114. If the progress line falls on the left side of the DD line, the activity is delayed, and vice versa. If activities have been completed (finish date is actualised), the progress line will be situated on the DD line. There are four options for presenting the progress line (you can change the options in the Progress line tab in the Bar chart options dialogue): Based on difference between current and baseline activity’s (1) finish and (2) start date; By connecting progress points on the basis of activity’s (3) Percent complete or (4) Remaining duration. Figure 114 – Progress line
When a scheduler finds updated progress data with delayed activities, he or she should first review the catch-up plans, and then check whether the delayed activities affect the completion date of the project or whether they become critical activities. If the catch-up plans show they will recover the delayed tasks, the scheduler should reduce the remaining duration of the delayed activity in the master schedule. On the other hand, if the catch-up plans show that they cannot recover and the delayed activities affect the completion date of the project or become critical activities, the scheduler may want to adjust successor activities’ durations to meet the original completion date. If the client has caused an activity to be delayed, the scheduler should prepare documents to claim an EOT (Extension of Time).
DELAY BY RETAINING LOGIC After updating, Primavera P6 users sometimes encounter an activity that cannot start as soon as all predecessor activities have finished; there is a reason, but it is difficult for novice users to find. Figure 115 below shows an example of activity delay. Initially, Activity C60 is scheduled to start 1 March, but it is automatically delayed when scheduling, even though its predecessor (C50) has already finished. Figure 115 – Sample schedule
The following reasons may account for this: (1) The start date of activities that have not started will be delayed to the DD; (2) lag is assigned to the relationship with its predecessor activity; (3) the assigned calendar has a non-work day on the date when the activity should have started; (4) the start date of the activity is constrained; (5) if the activity is Resource dependent, it can be delayed due to its resources’ constraints; (6) when P6 operators perform levelling resources, the activity can be delayed. However, none of these reasons applies to Activity C60. What happened to the activity? The answer is that its predecessor’s predecessor (C40) has not yet finished. The reasons listed above are related to the activity itself; however, delay caused by retaining logic can be found only when tracking its predecessors. On the other hand, a similar situation applies to Activity S10. Even though it has no Suspend and Resume date, its activity bar has been split because its predecessor’s predecessor (C40) has not yet finished. If you prefer to avoid these situations, select “Progress Override” in Schedule options, instead of “Retained Logic”. Figure 116 – Schedule options
Usually, schedulers do not know all the details of tasks (activities), so they link activities with FS relationships mostly; furthermore, clients require (recommend) contractors to use these types of relationships. However, in construction projects, a high rate of activities that are linked in FS can be linked in SS with lag. Progress override is recommended.
CORRECTIVE ACTIONS FOR DELAYED ACTIVITIES When the project schedule is delayed, schedulers should try to reduce or remove any lag in the schedule prior to performing corrective actions, as these actions may cause issues in terms of project cost, or interferences between predecessor and successor activities. Therefore, schedulers should add buffers to the project schedule to mitigate activity delays. The corrective actions in schedule management are techniques by which to recover the delayed activities so as to adhere to the project completion date. For efficiency, the corrective actions should be performed on critical activities first. There are two types of corrective actions for recovering delayed activities: crashing and fast-track. Crashing is a technique for reducing the durations of remaining activities by adding more resources based on Minimum cost expediting (MCE); fast-track is a technique for performing the remaining activities in parallel to compress the schedule. Figure 117 – Calculation of acceleration cost per day
To implement the crashing technique, costs for crashing should be analysed, as shown in Figure 117. If all activities on the table are on the same critical path, Activity E should be crashed first because its acceleration cost per day is the lowest ($10); this is the MCE technique. The acceleration cost per day is calculated as (Crash cost – Normal cost) / (Normal time – Crash time). Below are crashing methods for recovering delayed critical activities: •
Conduct overtime – Change calendar work hours/day from 8 hours to 12 hours per day, for example.
•
Enlarge working days – Change calendar working days from 5 days to 6 days per week, for instance.
According to schedule management theory, the fast-track technique does not increase costs to implement; however, rework can arise due to communication failure between predecessor activities and successor activities. Fast-tracking methods used in Primavera P6 change relationships from FS to SS with lag, as shown in Figure 118. Figure 118 – Example of fast-track
EXAMPLE OF EXPEDITING
CRASHING
BASED
ON
MINIMUM
COST
In Figure 119, a project has been delayed 10 days and a scheduler has to crash 10 days to meet the original project completion date. The blue boxes in the network schedule above the table are activities, and each of them has a letter and a number as its name and duration. The table below the schedule shows acceleration cost per day and remaining crash-able days. The critical path of the project is A-E-G-H, which will be reviewed first to apply the crashing technique. It is reasonable to reduce the duration of the critical activities because the project duration is dependent upon them. Activity E is the best one to reduce since it has the smallest acceleration cost ($10) among the four options (A, E, G, and H). Schedulers should minimise the increased cost when reducing durations. Figure 119 – Original schedule
The duration of Activity E can be reduced by only one day because the path A-B-C-D-H has also become a critical path, due to the reduced duration of Activity E. If Activity E is reduced by two days or more, the path A-E-G-H will become a non-critical path. Reducing a non-critical activity is not efficient. Now the total crashed duration is one day and the total cost for crashing is $10 in the first crashing, as shown in the table of Figure 120. Figure 120 – First crashing
Since there are two critical paths in the project, two paths should be reduced at the same time. If only one of them is reduced, the project duration will not change. In the schedule, Activities A and H are the critical activities, and they are linked with the two critical paths. In this case, reducing only one can reduce the project duration. After review, it has been found that Activity H has the smallest crashing cost ($20 per day); two days of its duration can be reduced. In the second crashing, the total crashed duration is three days, and $50 is the total cost for crashing. Figure 121 – Second crashing
The combination of Activities C and E has the smallest crashing cost ($35 per day); they can be reduced by two days. Figure 122 – Third crashing
Now Activity A is the best option; thus, its duration is reduced by three days, at an additional cost of $150. Figure 123 – Fourth crashing
Finally, the durations of Activities D and E have been reduced by two days, at a cost of $100. The total crashed duration is now ten days, and the total cost for crashing is $370. Thus, the average crashing cost per day is $37. Figure 124 – Fifth crashing
Even though crashing has been introduced here to demonstrate how to apply the technique, engineers should take into account the circumstances of field sites before
accelerating work. Typically, the crashing cost increases geometrically over the duration. To put it simply, if the crashing cost is $10,000 for 10 days for a project, the crashing cost for 20 days may be $30,000 or more, as shown in Figure 125. Figure 125 – Crashing and cost increase
PROCESS FOR REVISING THE PROJECT SCHEDULE It used to be that the project schedule was modified due to schedule delay, and rarely due to early-project-completion. No matter what the reasons for the schedule revision, schedulers should document the causes of the revision. If the reason comes from the client, the contractor will use the documentation for issuing claims; it can also be used as evidence in the dispute resolution phase later. Below are the steps for revising the project schedule: •
Document the grounds for the schedule revision.
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Prepare a draft proposal of the revised schedule.
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Analyse the impacts of the revised schedule in terms of time and cost.
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Finalise the proposal and submit it to the client.
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Get approval for the proposal from the client.
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Publish and distribute the revised schedule with a revision number to the counterparts and stakeholders.
Dos and don’ts for revising the schedule: •
Do not delete any activities to be erased in Primavera P6; instead, delete all relationships of an activity to be deleted and make its duration zero (0) in order to prevent reusing erased activities’ numbers.
•
Review resource constraints (Max units/time) again since resource allocation is also affected by delayed activities. Over-allocation can cause further delay.
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Mitigate resource peak.
Reporting EFFECTIVE PROGRESS REPORT The project progress report is not easy to write because planners and schedulers do not have enough time to spend collecting relevant information, composing a draft, and reviewing it. If there is anyone (perhaps one of the project management team members) who feels like he or she has been fumbling in the dark trying to prepare a good project status report, take the following recommendations into account: •
Keep schedule-related conditions in the contract agreement in mind. The progress report is a critical source for checking work performance, calculating payment, and solving disputes. Therefore, the report should include not only progress but also critical issues, as well as evidential material, if any.
•
Gauge the audience’s level of knowledge. Project progress reporting aims to help the client understand the project status and anticipate the end of the project.
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Include summaries in the report. To help the client understand the report, it is necessary to summarise the entire project progress.
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Highlight the updated elements. This is essential in regular reports, in which narratives are repeated.
•
Use tables and graphical elements. Sometimes tables, graphs, diagrams, and photos communicate more than words.
DEVELOPING REPORTS WITH PRIMAVERA P6 Even though Primavera P6 has features to create reports, they are not especially useful for preparing the project progress report because creating a report template takes quite a bit of time, and revising the template requires much effort. Nevertheless, if you want to create a report template in P6, follow these steps: •
Go to the Report window (Tools – Reports – Reports).
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Select a report template that you would like to use, and run Report Wizard (Tools – Report Wizard).
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Choose “Modify Wizard Report” and hit Next in the Report Wizard dialogue box.
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In the next dialogue box, select additional subject areas that you want to include in the report, and click Next to go to the next dialogue box.
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Modify columns, group and sort, and filter. Click Next to go to the next dialogue box. Change timescale and time interval fields, if any. Hit Next.
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Name it and hit Next.
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Uncheck format numbers and perform Run report.
SAMPLE MONTHLY PROGRESS REPORT Schedule performance reporting is the dissemination of meaningful information about the schedule’s overall status, progress to date, and forecast to complete. Schedule reporting helps determine if the project’s objectives (or requirements) are being met. The monthly progress report should consist of the following: The first part of the report will show overall status and statistics. •
Summary of this month’s project progress.
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Project progress (or Earned value analysis) – Shows the performed progress (Physical, in Primavera P6) of the month (Jul 2017), the accumulated progress, and planned progress of the next month (Aug 2017). See Figure 126.
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Activity status – Illustrates the actualised start and finish dates, delayed activities, and their reasons and recovery plans. See Figure 127.
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Rolling wave schedule. Figure 126 – Sample project progress table
Figure 127 – Example of activity status
The second part includes narratives and issues to explain the detail performances of each discipline, department, and subcontractor.
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Drawings, construction plans, construction
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Procurement
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Quality management
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HSE
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Cost management
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Document management
The third part will include critical documentary evidence.
PRINTING Any Primavera P6 layout can be printed. The output is customisable and can include any or all of the layout elements created on the screen. Additionally, header and footer data can be configured to add descriptive information and pictures. When you customise in Options tab in the Page setup dialogue box, some options (Profile, Spreadsheet, and Trace logic) may be deactivated (greyed). To print them, you need to display those figures by selecting a proper view mode in the Activities window. Figure 128 shows the relationships between print options and views in the Activities window. Figure 128 – Relationships between print options and view modes
PROBABILITY OF ON-TIME PROJECT COMPLETION What if a client asks you the probability of on-time project completion as currently planned? If you can operate Primavera Risk Analysis, you can compute it easily. Otherwise, you can determine the value using a time lapse of the project period. At the beginning of a project, the probability for on-time completion is very low, and it grows as the end of the project approaches. To be concrete, when 30% of the total duration has passed, the probability can be 30%, and when 80% has passed, it will be 80%. It is very
simple to compute time lapse: Ratio of time lapse = (OD – RD) / OD In this equation, OD is the original duration and RD is the remaining duration. For example, suppose there is a project with a total duration of 80 days. If the remaining duration of the project is 60 days, the progress is 25%. 25% = (80 – 60) / 80
HANDY TIP – DISPLAYING ALL ACTIVITY NAMES WHEN PRINTING OUT When printing out a schedule, the names of the activities near the end of the project duration will not be displayed fully, as shown in Figure 129. If you want to display the names fully, you can extend the timescale finish date in the Options tab of the Page setup dialogue box. The printed page will have large margins. Figure 129 – Print layout
If you want to display the names fully with small margins, follow the steps below: •
Create an activity code “LABEL” and a code value “Left” in the Activity codes dialogue box (see Figure 130) Figure 130 – Activity codes dialog box
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Set up columns to display the activity code “LEFT”.
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Make a filter, as shown in Figure 131. Figure 131 – Filter dialogue box
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Make a new bar in the Bars dialogue box.
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Name it “Label – Left” and choose Current bar for Timescale.
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Select “Label-left” for Filter, and make it invisible by selecting blank in Bar style.
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In the Bar labels tab, choose Left for position, and select Activity name for Label, as shown in Figure 132 Figure 132 – Bars dialogue box
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When you choose value “Left” for the activity code “LABEL”, you will see the label at the left side of the activity. Figure 133 – Adjusted label of a bar
SCHEDULE-RELATED CLAIMS AND ADVANCED TECHNOLOGIES
Delay analysis While implementing construction projects, contractors often encounter problems which were not foreseen at the beginning of the project, and which are not covered by the contract. These unforeseen problems cause schedule delay. To provide tangible reasons for this, schedulers should do a delay analysis on every event, or an activity delay, that has caused the project delay. Delay analysis is an analytical procedure specified on construction projects to facilitate the award of excusable days to project completion, due to delays that were not the responsibility of the contractor. There are many types of analytical methods to analyse the impact of a delay on the project: As-Planned versus As-Built Analysis, Window Analysis, Impacted As-Planned Analysis, Time Impact Analysis (TIA), Collapsed As-Built, etc. Among them, Window Analysis and TIA is used most often. The selection of a particular delay analysis method should be based on professional judgement because each claim is unique and deals with different contract requirements, levels of documentation, and situational contexts.
AS-PLANNED VERSUS AS-BUILT This method is used to compare the duration of all the activities on the As-planned schedule with the corresponding activities on the As-built (actual) schedule that are affected by the excusable delay events, especially the critical activities. It is very simple to use, but not appropriate for complicated schedules because it is very limited in its ability to define separate causes and effects when there are multiple issues. Thus, it is frequently used to support Global claims which record all causes of delay and ascribe the overall result to a combination of these causes, rather than linking causes to particular results. Figure 134 – As-planned versus As-built analysis
WINDOW ANALYSIS METHOD This approach is similar to the As-planned versus As-built. The key difference is the
assessment made within specific windows (e.g., monthly-basis) comparing planned and actual critical path (see Figure 135) so that the effects of the variance rate of progress in different periods of the project can be assessed. Responsibility for each delay is determined based on project documents, such as correspondence, weekly or daily reports, shop drawing submittals, testimony, etc. Figure 135 – Window analysis
IMPACTED AS-PLANNED This approach is based on the As-planned CPM model, in which schedulers insert the delay event (fragnet) to calculate the effect on overall completion. Thus, the delayed duration caused by an event can be different from the calculated time extension due to calendar settings, etc. In this method, the concurrent delays are taken into account. However, it does not show whether a delay to completion was actually incurred as a consequence of the modelled delay event. Figure 136 – Impacted As-planned analysis
TIME IMPACT ANALYSIS TIA, also known as Snapshot analysis or Time slice analysis, requires a CPM showing the differences between a schedule that includes an activity modelling a delay event and one that does not include the delay. This methodology is similar to the Impacted as-planned
analysis described above, but the delay event (fragnet) is applied to an updated schedule that represents the status of the project immediately prior to the event occurring. This is a form of Window analysis, as the effect of the delay is assessed on the basis of a contemporaneous baseline; multiple actual baselines may be used for different delays at different stages of a project. Being based on a dynamic model that has been accurately updated to reflect the current situation prior to the occurrence of the intervening event, this is probably the most accurate of the forward-looking delay assessment options available during the course of the work. When should TIA be performed? There are several points at which TIA may be required: •
Changes to planned work – This includes unforeseen changes to the work, such as discovery of conditions other than those in the plans.
•
Changes which affect contractor-owned float – This relates primarily to delays caused by the client.
•
Changes ordered by the client.
DETAIL PROCESS OF TIME IMPACT ANALYSIS Before beginning a TIA, schedulers should note that the accepted current schedule here will be called “the Unimpacted schedule” and the schedule for a TIA will be called “the Impacted schedule”. The steps for performing a TIA are as follows: •
Provide written notification of the event, in accordance with the conditions of the contract documents.
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Prepare the TIA form, as shown in Figure 137.
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Identify the delayed activity and create a new activity for it to represent delay fragnet under the same WBS, naming it “Delay –” + activity ID + TIA number. The structure of Activity ID numbering should be prepared in the planning phase of the project.
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Determine the accepted current schedule, which should be the schedule that has been updated prior to the time of the delay or change, and accepted by the client. Figure 137 – Example of TIA form
•
Update the unimpacted schedule. Prior to inserting the fragnet, the initial schedule must be updated to show the project progress up to the point of the delay. For most schedules, it is acceptable to use the last updated schedule with a DD close to the event.
•
Recalculate the schedule, record the predicted completion date of the unimpacted schedule, and make a copy of the impacted schedule.
•
Open the impacted schedule and create the fragnet, which will be a chain of activities representing the event and its duration to estimate the delay caused by the event. This could be one or two activities, or a whole sequence of activities. These activities should be linked in a logical order which shows how the contractor intends to perform the work.
•
Assign delayed duration and add relationships to the fragnet (activity F1010), linking it with logical predecessors and successors, which should be the affected activities, as shown in Figure 138. In other words, if Activity G1010 is delayed, a fragnet activity (F1010) is created and linked with both activities, G1010 and G1020, with FS relationships. Figure 138 – Adding a fragnet
•
Document the reasons for the assignment of the affected activities as successors.
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Recalculate the impacted schedule, using the same DD as the unimpacted schedule.
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Analyse changes to early start, early finish, and total float of the affected activities.
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Check whether the project completion date is delayed or there are any changes to the critical path, and document delay of the project completion date and changes of critical path, if any.
Dispute resolution and FIDIC The most common schedule-related critical issues in disputes between client and contractor are schedule delay, acceleration required by the client, and liquidated damage. When it comes to the entitlement of EOT and compensation, delay types can be categorised as follows: •
Non-excusable – Any delay caused by a contractor does not entitle the contractor to EOT or compensation.
•
Excusable but non-compensable – Any delay caused by an uncontrollable event, such as Force Majeure, entitles the contractor to EOT but not compensation.
•
Excusable and compensable – Any delay caused by the client entitles the contractor to EOT and compensation.
Schedule acceleration is always accompanied by a cost increase. Thus, schedulers should make clear which party has required the acceleration. •
Actual acceleration – The client requires the contractor to complete the project early.
•
Constructive acceleration – The client requires the contractor to complete the project on time, even though the client has delayed the project.
•
Acceleration for recovering – The contractor performs crashing or fast-tracking to recover a delayed project schedule.
As to liquidated damages due to failure to attain full load performance, or project completion delay, schedulers should know the limitation. Generally speaking, liquidated damages for project completion delay have a limitation – 10% of the total contract price, for example. Therefore, schedulers need to identify a daily-based penalty and its maximum for project completion delay in order to decide the maximum crashing cost per day.
FIDIC FIDIC (Fédération Internationale Des Ingénieurs-Conseils, The International Federation of Consulting Engineers) is an international organisation for the construction industry, and publishes international standard contract forms for clients, consultants, sub-consultants, joint ventures and representatives. Since FIDIC standard contract forms are commonly used in construction projects, the scheduler should become familiar with the contract templates in order to meet the conditions relevant to schedule management. The definitions in the FIDIC contract differ from the terminologies used in the schedule management field as follows: •
“Schedule” refers to the document(s) completed by the contractor and submitted with
the Letter of Tender, as included in the contract. Such document(s) may include the BOQ, data, and lists. •
“Programme” (or time programme) is used as a time schedule.
There are also definitions for persons, as follows: •
“Employer” means the project owner.
•
“Contractor” means the person(s) accepted by the employer.
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“Engineer” means the person(s) appointed by the employer to act as the engineer for the purpose of the contract.
•
“Subcontractor” means any person(s) appointed by the contractor for work.
SCHEDULE-RELATED CONDITIONS In a FIDIC contract template for Building and Engineering Works, the schedule-related conditions are as follows: •
1.9 Delayed Drawings or Instructions – The contractor shall give notice to the engineer whenever the work is likely to be delayed.
•
2.1 Right of Access to the Site – The employer shall give the contractor right of access to, and possession of, all parts of the site within the time (or times) stated in the contract.
•
4.21 Progress Report – Monthly progress reports shall be prepared by the contractor and submitted to the engineer. The report shall include charts, detailed descriptions of progress, and photographs showing the status of the progress of the site.
•
8.1 Commencement of Works – The engineer shall give the contractor not less than seven days’ notice of the commencement date. Unless otherwise stated in the conditions, the commencement date shall be within 42 days of the contractor receiving the letter of acceptance.
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8.2 Time for Completion – The contractor shall complete the whole of the works within the time for completion described in the contract.
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8.3 Programme – The contractor shall submit a detailed time programme to the engineer within 28 days of receiving the notice.
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8.4 EOT for Completion – The contractor may be entitled to an EOT for Completion for certain reasons.
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8.5 Delays Caused by Authorities – Any delays caused by the relevant legally constituted public authorities in the country.
•
8.6 Rate of Progress – The engineer may instruct the contractor to submit a revised programme and supporting report describing the revised methods which the contractor
proposes to adopt in order to expedite progress and complete work within the Time for Completion. •
8.7 Delay Damages – If the contractor fails to complete the work on time, the contractor shall pay delay damages to the employer for the default.
•
19.3 Duty to Minimise Delay – Each party shall use all reasonable endeavours to minimise any delay in the performance of the contract as a result of Force Majeure.
•
21.1 Contractor’s Claims – If the contractor considers himself to be entitled to any EOT for Completion, the contractor shall give notice to the engineer, describing the event or circumstance giving rise to the claim.
ISSUING CLAIMS A claim in construction projects is a request by a contractor for an EOT, additional payment, or some other relief under the terms of the contract or applicable law, but which the client refuses to grant to the contractor. Common causes of schedule-related claims include: •
Late issuance of NTP
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Late approval of drawings
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Late approval of shop drawings and samples
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Late approval of job test
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Delay in answer to field questions and field variances
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Delay due to improper management of work (inefficiency)
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Delay due to changes in the planned method of construction
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Disruption or interference by other contractors under the direction of the client
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Schedule changes by the client
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Client’s delay in supply of materials and facilities
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Suspensions of work by the client
•
Delay due to force majeure or acts of God
However, not all of these can be causes for claims because: •
Any claim must be based on the contract or applicable law.
•
A notice for a claim has to be transferred to the other party. FIDIC states that the contractor must give notice as soon as practicable, and not later than 28 days after becoming aware of the relevant event or circumstance giving rise to the claim.
•
Relationships between causes and effects must be proved. FIDIC states that within 42
days of the contractor becoming aware of the event or circumstance giving rise to the claim, or within such other period as may be proposed by the contractor and approved by the engineer, the contractor shall send to the engineer (the supervisor) a fully detailed claim which includes the extension of time and/or additional payment. •
Damages must be quantified. FIDIC limits the duration for computing quantities to 42 days.
When it comes to claims issuing, documentations is the first and best activities. Thus, team members should try to keep as many records and documents as possible. Below are the basic sources for proof of causation: •
Logs – Daily logs, telephone conversation logs, shop drawing logs
•
Records – Photographs, video tapes, equipment utilisation records, material delivery and receiving records, payment records, cost account records
•
Schedules – Schedules, cost flow schedule
•
Orders and requests – Change orders, requests for information
•
Reports – Daily reports, periodic status and progress reports, cost reports, Bid work sheets
•
Correspondence and meetings – Correspondence, internal correspondences, minutes of meetings
Below are structure of claim documents: •
Executive summary of claim
•
Overview or history of the project and claim: Project overview, summary of contract, history and cause of claim, contractor’s notification and client’s reply
•
Issue analysis: Issues and relevant conditions of the contract, proof of relationship between causes and effects
•
Impact and damage calculation: Schedule delay analysis, productivity loss analysis, cost impact analysis
•
Conclusion: Summary of issues and analyses
•
Appendix: Supporting documents
DISPUTE ADJUDICATION BOARD (DAB) AND THE DISPUTE RESOLUTION PROCESS To solve project-related disputes, people try to include all conditions in contract documents. However, contract documents cannot cover all the events that can happen during a project. Furthermore, disputes can occur easily between client and contractor because conditions in the contract do not include enough detail. Thus, the client and
contractor establish DAB for their disputes or use international arbitration to avoid spending a long time in court. Figure 139 – Dispute resolution process
FIDIC standard contracts introduce the DAB and the process of dispute resolution as follows (see Figure 139): •
Both parties (the contractor and the employer) appoint members of the DAB that will give their opinion when a dispute arises.
•
If either party denies to accept the opinion of the DAB, either party may give notice to the other party of its dissatisfaction within 28 days of receiving the decision.
•
Before the commencement of arbitration, both parties shall attempt to settle the dispute amicably.
•
Unless settled amicably, any dispute shall be finally settled by international arbitration.
Advanced technologies for schedule management Project management tools and methodologies have been developed that enable schedulers and participants to get information related to a project schedule in various ways.
4D SCHEDULE MANAGEMENT TOOL Sometimes, schedulers and engineers use tools (or software packages) that enable them to check their interface for issues. To do this, they should use their imaginative power with drawings and the project schedule. Suppose a three-dimensional drawing showing the construction process over the project period shows a basement with columns on top of it, and girders and slab above the columns. Some software packages can link the identities of 3D CAD drawings with activities in P6. As time goes on, each identity (object, block, or layer) linked with an activity appears based on the schedule, helping people to understand how a target building will be constructed. To actualise this simulation, drawings must be created on the basis of drawing standards which define drawing layers and block names in a drawing. Software packages can also include a feature that compares a real scene in the field site camera with 3D CAD drawings of a virtual scene.
SCHEDULE BALANCE
PRESENTING
METHODOLOGIES
–
LINE
OF
Line of balance (LOB) is a simple diagram showing the location (or units) and time at which a certain deliverable is completed. In some construction projects, this technique is already used to monitor and compute work performance. The advantage of using this tool is to help schedulers clearly view trends of performance and forecast the interference between the predecessor and the successor tasks. Below are common applications of LOB in schedule management: •
Floor-time diagram – This looks similar to a Time-distance diagram (see Figure 7), with a Y-axis for the floors of a building and an X-axis for time scale, as shown in Figure 140. It is a very simple schedule, but it is powerful for reviewing interferences between disciplines and calculating performance for each task. Figure 140 – Sample Floor-time diagram
•
Unit-time diagram – This is also similar to a Floor-time diagram, and is used to
manage resources. If a project has serious constraints in procuring and managing resources, this diagram will help schedulers comprehend the demand curve of resources. The picture above shows a general bar chart schedule in which activities are displayed with resources. For example, Activity 1 is loaded with Labour A (LA) and Activity 2 has Machine A (MA). The image below shows a resource usage schedule in which blue lines represent planned resource cumulative units and red lines represent actual resource cumulative units over the period. You can create it with the data of Resource usage spreadsheet in Primavera P6. Figure 141 – Bar chart schedule and Unit-time diagram
XML FORMAT XML is a mark-up language that defines a set of rules for encoding documents, originally developed for the web as a companion to HTML. When importing or exporting in Primavera P6 PPM (version 15.1), you may have seen two XML options: Primavera(XML) and UN/CEFACT format 6-(XML). Their languages differ slightly, as shown in Figure 142. Figure 142 – Exporting a project in XML format
Since an XML-formatted P6 file is actually more versatile than an XER file, some government agencies in the U.S., such as the Department of Defense, submit schedules in the UN/CEFACT XML schema format.
RECOMMENDATIONS FOR UPGRADING PRIMAVERA P6 PPM
Primavera P6 PPM (the current version is 15.1) is a powerful software package for schedule management; however, some features still need to be upgraded, as follows: •
Freezing pane in the activity table – The Activity window is separated into three sections (activity table, Gantt chart, and details). P6 operators frequently adjust columns in the activity table or save and open layout to view columns; however, sometimes users need to view many columns at the same time. In that case, they have to move horizontal scroll to view some right side, and moving scroll makes activity numbers and names hidden from view on the left side. If users can freeze columns of activity numbers and names, they will save time adjusting columns.
•
Grouping columns in the activity table – We wish we could group columns and expand and collapse them.
•
Filter – We wish we could filter in different ways, as we do in Excel.
NAM – A new approach to analysing the project schedule When it comes to contract conditions, progress during the implementation phase is less important than completing the project on time, as many claims arise due not to performance but schedule delay. Moreover, high performance as measured by EVM does not guarantee earlier or on-time completion of a project, as mentioned earlier. Even though SPI in following figure indicates good performance (1.4) on the DD, the project will be delayed because of Component B. Often, EVM makes schedulers fail to properly expect the project completion date.
As a result, schedulers should focus on project duration rather than project performance. Based on this background, the author suggested Network Analysis Method (NAM) in his Master’s dissertation for efficient project duration management.
DEFINING THE PRIORITY OF NEAR-CRITICAL PATHS TO MONITOR Project duration is determined by the duration of the critical path; however, rather than being fixed, the critical path changes due to delays of near-critical activities, so schedulers need to monitor near-critical paths as well in order to meet the project period. If there are two near-critical paths (not activities) as follows, which will more likely become the critical path? (The longest path in the schedule option is preferable for defining nearcritical paths.) •
Path A – Its total duration is 10 days and total float is 3 days.
•
Path B – Its total duration is 100 days and total float is 4 days.
According to analysis in Primavera P6 (Float path), Path A will have a higher priority because of the smaller total float. In fact, Path B has a higher probability of becoming the critical path because it has more risks due to longer duration; a task with a long duration usually has a large amount of quantity, or numerous stages, or both. Thus, in NAM, the
priority of near-critical paths is defined based on the Criticality Quotient (CQ), calculated as:
Calculating the CQ of each path, Path A is 30 and Path B is 4. A lower number means a higher probability of becoming the critical path. In NAM, the near-critical path with the lowest CQ is called the first near-critical path, the path with the second lowest CQ is called the second near-critical path, and so on. The total duration of the path in the equation is not the period from the first activity to the last activity but the total amount of the activities’ durations on the path. For instance, suppose there are three near-critical paths with the same duration, as shown in Figure 143. Path 2 has more risks for being delayed than Path 1 because it has two activities with long durations. On the other hand, Path 3 has fewer risks than Path 1 because it has lag, which can act as a buffer when Activities I or J are delayed. Figure 143 – Comparison of near-critical paths
MONITORING NEAR-CRITICAL PATHS The table below shows an example of near-critical paths monitoring monthly-base, where TF is total float, RD is remaining duration, and CQ is criticality quotient. As of 31 January 2018, Path A’s TF was two days, the total amount of its activities’ RD was 60 days, and its CQ was three. As of 28 February, its RD has decreased to 40 days because some activities on the path have been completed. Since its RD has decreased, its CQ has increased. In the case of Path B, its CQ has continuously decreased, and a scheduler should pay attention to the path. The five paths with the lowest CQs would be enough for monitoring. Figure 144 – Example of near-critical paths monitoring
Figure 145 – Trends of each path’s CQ
Figure 145 illustrates the trend of each path’s CQ. As you can see, most CQ has decreased. The trends suggest that the project schedule is pressed to delay.
CONCLUSION NAM is a method for analysing float path and monitoring the total float of each path to define the pressure of project delay. NAM also helps focus on the important (critical) activities in managing the schedule to meet the project duration. To use NAM, the priority of near-critical paths should be redefined based on duration and total float. Its CQ should be measured regularly to monitor the pressure of project delay.
APPENICES
Acronyms •
AC: Actual Cost
•
AON: Activity on Node
•
BAC: Budget at Completion
•
BOQ: Bill of Quantity
•
BPM: Backward Pass Method
•
CA: Cost Accounts
•
CAD: Computer Aided Drawing
•
CCM: Critical Chain Method
•
CCPM: Critical Chain Project Method
•
COA: Code of Accounts
•
CPI: Cost Performance Index
•
CPM: Critical Path Method
•
CQ: Criticality Quotient
•
CRC: Cost-Reimbursement Contract
•
CV: Cost Variance
•
CWS: Contractor Working Schedule
•
DAB: Dispute Adjudication Board
•
DCL: Data Control Language
•
DCMA: Defense Contract Management Agency (USA)
•
DD: Data Date
•
DDL: Data Definition Language
•
DML: Data Manipulate Language
•
EAC: Estimate at Completion
•
EOT: Extension of Time
•
EPPM: Enterprise Portfolio Project Management
•
EPS: Enterprise Project Structure
•
ETC: Estimate to Complete
•
EV: Earned Value
•
EVM: Earned Value Method
•
FDU: Fixed Duration & Units
•
FDUT: Fixed Duration and Units/Time
•
FF: Finish-to-Finish
•
FIDIC: Fédération Internationale Des Ingénieurs-Conseils
•
FPC: Fixed-Price Contract
•
FPM: Forward Pass Method
•
FS: Finish-to-Start
•
FU: Fixed Units
•
FUT: Fixed Units/Time
•
GERT: Graphical Evaluation and Review Technique
•
HSE: Health, Safety, and Environment
•
IC: Incentive Contract
•
IDC: Indefinite-Delivery Contract
•
IPS: Integrated Project Schedule
•
LHC: Labour-Hour Contract
•
LOB: Line of Balance
•
LOE: Level of Effort
•
MCE: Minimum Cost Expediting
•
MPM: Monthly Progress Meeting
•
MPR: Monthly Progress Report
•
MSS: Milestone Summary Schedule
•
NAM: Network Analysis Method
•
NGO: Non-Governmental Organisations
•
OBS: Organisation Breakdown Structure
•
OD: Original Duration
•
PDM: Precedence Diagramming Method
•
PERT: Program Evaluation and Review Technique
•
PMC: Project Management Consultancy
•
PMI: Project Management Institute
•
PMIS: Project Management Information System
•
PMP: Progress Measurement Procedure
•
PPM: Professional Project Management
•
PRA: Primavera Risk Analysis
•
PV: Planned Value
•
RAM: Responsibility Assignment Matrix
•
RD: Remaining Duration
•
SAR: Schedule Analysis Report
•
SCP: Schedule Controlling Procedure
•
SDK: Software Development Kit
•
SDP: Schedule Development Procedure
•
SF: Start-to-Finish
•
SPI: Schedule Performance Index
•
SQL: Structured Query Language
•
SS: Start-to-Start
•
SV: Schedule Variance
•
TIA: Time Impact Analysis
•
TMC: Time-and-Materials Contract
•
TOC: Theory of Constraints
•
UDF: User Defined Field
•
WBS: Work Breakdown Structure
Calculation of data fields used in Primavera P6 •
Accounting Variance = Planned Value – Actual Cost.
•
Accounting Variance-Labour Units = Planned Value Labour Units – Actual Units.
•
Activity % Complete = [If the selected activity’s percent complete type is Duration] (Planned Duration – Remaining Duration) / Planned Duration. [If the activity’s percent complete type is Units] (Actual Labour Units + Actual Nonlabor Units) / (Actual Labour Units + Actual Nonlabor Units + Remaining Labour Units + Remaining Nonlabor Units).
•
Actual Cost (Assignments) = Actual Regular Cost + Actual Overtime Cost.
•
Actual Cost (EPS) = Actual Labour Costs + Actual Nonlabor Costs + Actual Material Costs + Actual Expense Costs.
•
Actual Cost (Expenses) = Actual Units X Price/Unit.
•
Actual Labour Cost = [If no resources are assigned] Actual Labour Units X Project Default Price / Time.
•
Actual Nonlabor Cost = [For activities, If no resources are assigned] Activity Actual Nonlabor Units X Project Default Price / Time.
•
Actual Overtime Cost = Actual Overtime Units X Cost per Time X Overtime Factor.
•
Actual Regular Cost = Actual Regular Units X Cost per Time.
•
Actual This Period Cost = [If period performance is stored] Actual Cost – the sum of the stored Actual This Period Cost fields for all previous periods. [If the period performance is not stored] Actual This Period Cost is the same as Actual Cost.
•
Actual This Period Labour Cost = [If period performance is stored] Actual Labour Cost – the sum of the stored Actual This Period Labour Cost fields for all previous periods. [If the period performance is not stored] Actual This Period Labour Cost is the same as Actual Labour Cost.
•
Actual This Period Labour Units = [If period performance is stored] Actual Labour Units – the sum of the stored Actual This Period Labour Units fields for all previous periods. [If the period performance is not stored] Actual This Period Labour Units is the same as Actual Labour Units.
•
Actual This Period Material Cost = [If period performance is stored] Actual Material Cost – the sum of the stored Actual This Period Material Cost fields for all previous periods. [If the period performance is not stored] Actual This Period Material Cost is the same as Actual Material Cost.
•
Actual This Period Nonlabor Cost = [If period performance is stored] Actual Nonlabor
Cost – the sum of the stored Actual This Period Nonlabor Cost fields for all previous periods. [If the period performance is not stored] Actual This Period Nonlabor Cost is the same as Actual Nonlabor Cost. •
Actual This Period Nonlabor Units = [If period performance is stored] Actual Nonlabor Units – the sum of the stored Actual This Period Nonlabor Units fields for all previous periods. [If the period performance is not stored] Actual This Period Nonlabor Units is the same as Actual Nonlabor Units.
•
Actual This Period Units = [If period performance is stored] Actual Units – the sum of the stored Actual This Period Units fields for all previous periods. [If the period performance is not stored] Actual This Period Units is the same as Actual Units.
•
Actual Total Cost (Activities) = Actual Labour Cost + Actual Nonlabor Cost + Actual Material Cost + Actual Expense Cost.
•
Actual Total Cost (EPS) = Actual Labour Costs + Actual Nonlabor Costs + Actual Material Costs + Actual Expense Costs.
•
Actual Units (Assignments) = Actual Regular Units + Actual Overtime Units.
•
At Completion Cost = Actual Costs + Remaining Costs.
•
At Completion Expense Cost = Actual Expense Cost + Remaining Expense Cost.
•
At Completion Labour Cost = Actual Labour Cost + Remaining Labour Cost.
•
At Completion Labour Units = Actual Labour Units + Remaining Labour Units.
•
At Completion Material Cost = Actual Material Cost + Remaining Material Cost.
•
At Completion Nonlabor Cost = Actual Nonlabor Cost + Remaining Nonlabor Cost.
•
At Completion Nonlabor Units = Actual Nonlabor Units + Remaining Nonlabor Units.
•
At Completion Total Cost = Actual Total Cost + ETC (estimate-to-complete) cost.
•
At Completion Units = Actual Units + Remaining Units.
•
BL Duration = Actual Duration + Remaining Duration.
•
BL Project Duration = Actual Duration + Remaining Duration.
•
BL Project Total Cost = BL Project Labour Cost + BL Project Nonlabor Cost + BL Project Material Cost + BL Project Expense Cost.
•
BL1 Duration = Actual Duration + Remaining Duration.
•
BL1 Labour Units = Baseline Actual Labour Units + Baseline Remaining Labour Units.
•
Budget At Completion = Planned Labour Cost + Planned Nonlabor Cost + Planned Expense Cost + Planned Material Cost.
•
Cost % Complete = Actual Total Cost / At Completion Total Cost X 100.
•
Cost % of Planned = Actual Total Cost / Baseline Total Cost X 100.
•
Cost Performance Index = Earned Value Cost / Actual Cost.
•
Cost Performance Index-Labour Units = Earned Value Labour Units / Actual Labour Units.
•
Cost Variance = Earned Value – Actual Cost.
•
Cost Variance-Labour Units = Earned Value Labour Units – Actual Labour Units.
•
Cost Variance Index = Cost Variance / Earned Value.
•
Cost Variance Index-Labour Units = Cost Variance Labour Units / Earned Value Labour Units.
•
Current Budget = Original Budget + the sum of the approved budget changes from the budget log.
•
Current Variance = Current Budget – Total Spending Plan.
•
Days Pending = the Current Date – the Assigned Date of the oldest currently assigned human task for the currently logged in user.
•
Duration % Complete = Planned Duration – Remaining Duration / Planned Duration X 100.
•
Duration % of Planned = Actual Duration / Baseline Duration X 100.
•
Duration Percent = (Planned Duration – Remaining Duration) / Planned Duration X 100.
•
Earned Value Cost = Budget At Completion X Performance Percent Complete.
•
Earned Value Labour Units = [Activity Level] BL Project Labour Units or BL1 Labour Units X Performance % Complete, depending on project settings. [WBS Level] BL Project Labour Units X Performance % Complete.
•
Estimate At Completion-Labour Units = Actual Labour Units + Estimate to Complete Labour Units.
•
Estimate At Completion Cost = Actual Cost + Estimate to Complete Cost.
•
Estimate To Complete = Remaining Total Cost for the activity or the Performance Factor X (Budget At Completion – Earned Value), depending on the Earned Value technique selected for the activity’s WBS.
•
Estimate To Complete Labour Units = either the Remaining Total Units for the activity or as Performance Factor X (BL Labour Units – Earned Value) depending on the earned-value technique selected for the activity’s WBS.
•
Expense Cost % Complete = Actual Expense Cost / At Completion Expense Cost X 100. Always in the range 0 to 100.
•
Exposure = probability midpoint X cost midpoint.
•
External Early Start = [If the relationship type is Start to Finish or Finish to Finish] Relationship Early Finish Date – Remaining Duration of the successor.
•
External Late Finish = [If the relationship type is Start to Start or Start to Finish] Relationship Late Start + Remaining Duration of the predecessor.
•
Forecast at Completion: Cost (Earned Value Performance) = Budget at Completion X Cost Variance Index (CVI).
•
Forecast at Completion: Cost (Schedule Performance) = Budget at Completion – Estimate at Completion.
•
Forecast at Completion: Labour Units (Earned Value Performance) = Baseline (BL) Labour Units X Cost Variance Index (CVI) Labour Units.
•
Forecast at Completion: Labour Units (Schedule Performance) = Budget at Completion Labour Units – Estimate at Completion Labour Units.
•
Forecast at Completion: Schedule (Earned Value Performance) = [For costs] Budget at Completion X Schedule Variance Index (SVI).
•
Forecast at Completion: Schedule (Schedule Performance) = Remaining Finish Date – Baseline Finish Date.
•
Labour Cost % Complete = Actual Labour Cost / At Completion Labour Cost X 100.
•
Labour Units % Complete = Actual Labour Units / At Completion Labour Units X 100.
•
Material Cost % Complete = Actual Material Cost / At Complete Material Cost X 100.
•
Net Present Value = Total Benefit Plan (Present Value) – Total Spending Plan (Present Value).
•
Nonlabor Cost % Complete = Actual Nonlabor Cost / At Completion Nonlabor Cost X 100.
•
Nonlabor Units % Complete = Actual Nonlabor Units / At Completion Nonlabor Units X 100.
•
Overtime Factor = Standard Price X Overtime Factor.
•
Planned Labour Cost (Activities) = [If no resources are assigned] Activity Planned Labour Units X Project Default Price / Time.
•
Planned Nonlabor Cost = [If no resources are assigned] Activity Planned Nonlabor Units X Project Default Price / Time.
•
Planned Value Cost (Activities) = Budget At Completion X Schedule Percent Complete.
•
Planned Value Labour Units (Activities) = Budget At Completion X Schedule Percent Complete.
•
Planned Value Labour Units (EPS) = Baseline Labour Units X Schedule Percent Complete.
•
Proposed Budget = Original Budget + the sum of the Approved and Pending Budgets from the budget log.
•
Remaining Cost (Assignments) = Remaining Units X Cost/Time.
•
Remaining Cost (Expenses) = Remaining Labour Costs + Remaining Nonlabor Costs + Remaining Expense Costs.
•
Remaining Float = Late Finish – Remaining Finish.
•
Remaining Labour Cost (Activities) = [If no resources are assigned] Activity Remaining Labour Units X Project Default Price / Time.
•
Remaining Nonlabor Cost (Activities) = [If no resources are assigned] Activity Remaining Nonlabor Units X Project Default Price / Time.
•
Remaining Units (Activities) = Planned Units – Actual Units.
•
Remaining Units (Assignments) = Remaining Duration X Remaining Units per Time.
•
Return on Investment = Net Present Value / Total Spending Plan (Present Value).
•
Schedule Performance Index-Labour Units = Earned Value Labour Units / Planned Value Labour Units.
•
Schedule Performance Index (Earned Value) = Earned Value / Planned Value.
•
Schedule Performance Index (Index Performance) = Earned Value of Cost or Quantity / Planned Value of Cost or Quantity.
•
Schedule Variance = Earned Value – Planned Value.
•
Schedule Variance-Labour Units = Earned Value Labour Units – Planned Value Labour Units.
•
Schedule Variance Index-Labour Units = Schedule Variance Labour Units / Planned Value Labour Units.
•
Schedule Variance Index (Activities) = Schedule Variance / Planned Value.
•
Schedule Variance Index (EPS) = Schedule Variance Labour Units / Planned Value Labour Units.
•
Score (Resource Search Results) = Available units of the resource across the expanded
activity time frame – Total Requested Units. •
Step Weight Percent = (Step Weight / Sum of Weight for all steps) X 100.
•
To Complete Performance Index (Earned Value) = (Budget at Completion – Earned Value) / (Estimate at Completion – Actual Units or Cost).
•
To Complete Performance Index (Index Performance) = (BAC – Earned Value) / (EAC – Actual Units or Cost).
•
To Date: Cost = Earned Value Cost – Actual Cost.
•
To Date: Labour Units = Earned Value Labour Units – Actual Labour Units.
•
To Date: Schedule (Earned Value) = [For costs] Earned Value Cost – Planned Value Cost.
•
For labour units, Earned Value Labour Units – Planned Value Labour Units.
•
To Date: Schedule (Schedule Performance) = (Baseline Duration X Performance % Complete) – (Baseline Duration X Schedule % Complete).
•
Total Benefit Plan = Plan Period $ / (1 + Annual Discount Rate) X years.
•
Total Float = Late Start – Early Start or Late Finish – Early Finish.
•
Total Present Value (Discounted): Benefit Plan = Plan Period $ / ((1 + Discount Rate) to the nth power).
•
Total Spending Plan = Plan Period $ / (1 + Annual Discount Rate) X years.
•
Unallocated Budget (EPS) = Total Current Budget – Distributed Current Budget.
•
Units % Complete (Activities) = Actual Units / At Completion Units X 100.
•
Units % Complete (Assignments) = Actual Units / At Completion Units X 100.
•
Units % Complete (EPS) = Actual Units / At Complete Units X 100.
•
Variance-Duration = Baseline Duration – At Completion Duration.
•
Variance-Expense Cost = Project Baseline Expense Cost – At Completion Expense Cost.
•
Variance-Finish Date = Finish Date – Baseline Finish Date.
•
Variance-Labour Cost = BL Labour Cost – At Completion Labour Cost.
•
Variance-Labour Units = Baseline Labour Units – At Completion Labour Units.
•
Variance-Material Cost = Project Baseline Planned Material Cost – At Completion Material Cost.
•
Variance-Nonlabor Cost = BL Nonlabor Cost – At Completion Nonlabor Cost.
•
Variance-Nonlabor Units = Baseline Nonlabor Units – At Completion Nonlabor Units.
•
Variance-Start Date = Start Date – Baseline Start Date.
•
Variance-Total Cost = BL Total Cost – At Completion Total Cost.
•
Variance At Completion = Budget At Completion – Estimate At Completion.
•
Variance At Completion-Labour Units = Project Baseline Planned Total Labour Units – Estimate At Completion Labour Units.
•
Variance BL Project-Duration = Planned Duration – At Completion Duration.
•
Variance BL Project-Expense Cost = BL Project Expense Cost – At Completion Expense Cost.
•
Variance BL Project-Finish Date = Finish – BL Project Finish.
•
Variance BL Project-Labour Cost = Planned Labour Cost – At Completion Labour Cost.
•
Variance BL Project-Labour Units = BL Project Labour Units – At Completion Labour Units.
•
Variance BL Project-Material Cost = BL Project Material Cost – At Completion Material Cost.
•
Variance BL Project-Nonlabor Cost = Planned Nonlabor Cost – At Completion Nonlabor Cost.
•
Variance BL Project-Nonlabor Units = BL Project Nonlabor Units – At Completion Nonlabor Units.
•
Variance BL Project-Start Date = Start – BL Project Start.
•
Variance BL Project-Total Cost = Planned Total Cost – At Completion Total Cost.
•
Variance BL1-Duration = BL1 Duration – At Completion Duration.
•
Variance BL1-Expense Cost = Primary Baseline Expense Cost – At Completion Expense Cost.
•
Variance BL1-Finish Date = Finish – BL1 Finish.
•
Variance BL1-Labor Cost = BL1 Labour Cost – At Completion Labour Cost.
•
Variance BL1-Labor Units = BL1 Labour Units – At Completion Labour Units.
•
Variance BL1-Material Cost = BL1 Material Cost – At Completion Material Cost.
•
Variance BL1-Nonlabor Cost = BL1 Nonlabor Cost – At Completion Nonlabor Cost.
•
Variance BL1-Nonlabor Units = BL1 Nonlabor Units – At Completion Nonlabor Units.
•
Variance BL1-Start Date = Start – BL1 Start.
•
Variance BL1-Total Cost = BL1 Total Cost – At Completion Total Cost.
References •
FIDIC (1999). Conditions of Contract for Construction (Building and Engineering Works, 1st Edition). FIDIC publications.
•
Nam, J (2012). Time Management in Railway Construction. University of Birmingham.
•
Oracle (2014). Primavera P6 Data Dictionary Release 8.3. Oracle.
•
PMI (2013). PMBOK Guide 4th Edition. Pennsylvania: PMI Publications.
