Practitioner's Guide

Welcome to Project Controls Practitioner's Guide to Key Topics

You are now at the location for what will soon be THE most extensive Project Controls guide on key topics and concepts to be found anywhere on the web. This guide will be under constant update and revision and hence we can never say it is complete. To help us produce this quality service, we request practitioners to contribute with feedback, suggestions and content revision.


  • 1) Planning Definition
  • 2) Planning Elements
  • 2.1) Scope of Work (WBS)
  • 2.2) Method of Execution (Logic Network)
  • 3) Scheduling Definition
  • 4) CPM Scheduling
  • 5) Schedule Hierarchy
  • 5.1) Schedule Baseline and Process
  • 6) Key Concepts
  • 6.1) Float & Types
  • 6.2) Resource Scheduling
  • 6.3) Schedule Analysis

1) Definition of Planning:

Simplistic definition of planning is "making decisions with the objective of influencing the future" i.e.,

  • • What tasks will be performed?
  • • How tasks will be performed?
  • • In what sequence the tasks will be performed?
  • • Who will perform the tasks?

2) Planning Elements

Key Planning Elements are Scope of Work which is transpired in Work Breakdown Structure (WBS) and Method of Execution which is identified in the logic diagram. Let us understand both these elements.

2.1) Work breakdown Structure:

The PMBOK Guide defines a WBS as a deliverable, orientated grouping of project elements, that organizes and defines the total scope of the project. By using a WBS, it allows the project team to plan a project by means of a hierarchical structure, by identifying the elements and sub elements. A work package, usually at the lowest level of a WBS, includes a series of tasks to be carried out as part of an element of work. The WBS is interfaced with the project plan and the coding structure within the WBS, allow reporting of cost and schedule forecasts to deliver the schedule and cost reports. Recent developments have initiated a Cost Breakdown Structure (CBS), which links to the WBS, but allows increased details of monitoring and cost control to take place.

2.2) Critical Path Logic Diagram:

The critical path logic diagram is the process of recording and presenting the logical interfaces between schedule activities. A more common name for this type of diagram is a PERT chart; which is short for Programme Evaluation Review Technique. The critical path logic diagram is created as a series of schedule activities represented by a box for each activity. Each activity box is linked to its dependencies by lines with arrow heads to show the sequence of the dependencies. The activity description is included in the information for each box. Traditionally the activity boxes and arrows are presented starting on the left and ending on the right. The completed series of activities and dependencies is the precedence network. The PERT chart facilitates the review of relationships without respect to time and is used particularly during project schedule development to confirm and revise logic.

A pure logic diagram, may be developed by hand or by the use of software tools such as Primavera P6 / SureTrak / Microsoft Project. Using any of these tools, the full network of activities are input systematically to allow logical considerations to be reviewed, with respect to each activity. The logic diagram is populated with durations, assessed as reasonable allowances for each activity, and if practical start and finish dates. After inputting all the activity durations, the network can be processed to identify the route between those activities from start to end of the project that will provide the least duration of the project. This duration and the path highlighting those activities, represents the critical path for the project. The importance of the critical path is that if any progress measurement reports the failure of an individual activity to be completed in the allowed duration, will result in the whole project failing to complete in the required time scale. The critical path should be closely monitored for progress. A failure of an activity on the critical path to meet its completion date may, however, change the subsequent sequence of activities that are the critical path, and the logic diagram should be processed in such an occurrence to confirm the current critical path and the component activities. The populated logic diagram can be used to explore and select from option plans and what if scenarios by altering durations of individual activities, to reflect alternative procurement strategies or construction processes.

3) Scheduling Definition

Scheduling is determination of timing of events in the project i.e., When tasks will be performed? Simplistically, It’s a reflection of plan. In other words, planning is how, what and who whereas, Scheduling is When and Why. Schedule can also be defined as detailed plan of the project work tasks with respect to time.

Scheduling serves as catalyst to communications i.e., Scope, Work Definition, Sequencing & Logic, Resource Allocation and What if Analysis. Scheduling also provides comparison of actual progress against plan and help identify deviations from plan. Scheduling also enables early corrective actions and adjustments to plan.

4) CPM Scheduling

Critical Path Method Scheduling is based on Critical Path Method (CPM) which can be defined as "The Calculation of the earliest and latest start and finish dates of activities based on their durations and relationship to other activities"

CPM Calculations overview:

  • • The determination of the earliest start and finish dates, and the latest start and finish dates of every activity in the network.
  • • Early dates indicate the earliest start and finish dates when an activity can be performed if all preceding activities have been completed.
  • • Late start and finish dates are the latest dates an activity can be performed without delaying the project.

5) Schedule Hierarchy & Process

Defines the schedule control system and several interrelated levels of schedules at various levels. Schedule hierarchy provides a framework for project schedule development.

Primarily there are following 4 level of schedules being applied on medium to large size projects to identify the scope and division and as well as contractual/project milestones.

Level I: Milestone Summary Schedule - Depicts overall time frame of project, covers total project scope and highlights contractual and Project milestones. This schedule is used by Management to highlight major and significant events as well as to communicate overall scope and status of project. This level schedule can also be used for decision making.

Level II: Summary Schedule - Level II Schedule is summarised by facility, discipline and areas for Engineering, highlighting long lead items, critical items for Procurement, and summarised by work package for Construction. Level II schedule establish requirements at the facility level, phase or work phase. It depicts the relationship between facilities/phases and establish facility criticality.

Level III: Detailed Engineering, Procurement and Construction Schedule - Integrated EPC Schedule where Engineering is sorted by discipline, grouped by systems/area depicting system requirement. Procurement identifies demand by facility/area or systems and as well identify the major equipment delivery. Construction/startup is grouped by system/area depicting interrelationships and timeframes. Level III Schedules establish the basis for staff requirements Task deliverables, material and subcontract requirements and bull release and installation rates. Level III schedule establish construction equipment requirements and integrates facility/area breakdown into system turnover packages. Level III schedules are maintained at regular basis and used for What-if analysis.

Level IV: Identification of detailed work plan, log list etc - Level IV schedule is broken down at work activity level i.e., drawings, specs, data sheets etc. It depicts construction by work package/area/facility/craft/crew and establish construction sequence. Level IV schedule provides basis for detail construction work planning and rolling schedules and its a working document that is continually updated and revised to reflect project needs and circumstances.

5.1) Schedule Baseline Process and types

Schedule must be baselined to map it to current schedule to avoid slipages and to get early warnings. This also assists in developing planned S Curves and histograms to keep the current schedule on track.

6) Key Concepts ;

6.1) Float & Types

Definition of Float:

Float is the product of the critical path analysis. It identifies the extent to which any activity can be delayed and not impact the completion of the project. It is important to understand that the float on any activity is not there for the people on that activity to use. Also, Float on an activity does not confer the right to delay an activity.

So who owns the Float? Well, sharing float concepts influences the ownership and hence it varies as below:

  • • Complex jobs - courts have held that legal ownership of float belongs to the project...not contractor or owner.
  • • The party(s) responsible for overall coordination control dictates the use of float.

Types of floats: Total Float, Free Float and Negative Float

Total Float: Amount of time an activity can exceed its early finish date without affecting the project end date or other imposed dates.

Free Float: Amount of time by which an activity can exceed its early finish date without affecting the early start date of any successor(s).

Negative Float: Amount of time that the start or finish of any activity exceeds the time allowed.

6.2) Resource Scheduling:

Resource Scheduling defines which resource should be used on specific tasks-between which dates. It analytically manages and use schedule float. It also analyse staffing requirements and evaluate effects of limited staffing and in thus avoid wide fluctuations in daily need for various resources. Resource scheduling helps significantly in producing more realistic schedules better progress curves, and staffing curves. Good resource scheduling is the basis for maximising the productivity of people and equipment while minimising their cost.

Resource Scheduling in P6 (Oracle Primavera P6) can be done using its bucket planning feature. What is bucket planning ?

A bucket is another term for "timeperiod." In Primavera applications, you can view, enter, and edit activity and assignment data in various buckets, such as daily, weekly, monthly, quarterly, yearly, and financial period. The term "bucket" is generally used in future period bucket planning, which enables you to manually enter and edit assignment data for some activities in future.

What is future period bucket planning ?

Ans : When you specify an activity's total budgeted units, the budgeted units for an assignment to that activity are spread evenly across the duration of the activity, in the timescale increment you choose. For example, a four-week activity with 80 budgeted units is spread as follows, assuming a weekly timescale: Week 1 – 20hours, Week 2 – 20 hours, Week 3 – 20 hours, Week 4 – 20 hours. However, your projects may contain activities for which you know work will be performed sporadically and at varying levels of effort. For these activities, you can do either of the following to more accurately capture when you plan for work to be performed on an activity:

  • 1) Assign a Resource Curve to the resource/role assignment.
  • 2) Manually enter the assignment’s budgets units or remaining units in future period buckets (timeperiods)

While assigning a resource curve to the resource/role assignment will yield more accurate results than spreading units evenly across the duration of an activity, the work you plan to perform per period on an activity may not be fully reflected by the curve. As a result, performance against the project plan cannot be accurately measured.

To achieve the most precise resource/role distribution plan, you can manually enter the budgeted resource/role allocation per assignment in the timescale unit you choose (days, weeks, months, quarters, years, or financial periods). For example, assume an activity has an original duration of 28 days and budgeted units of 80 hours. For this activity, you know that the actual work will not be spread evenly across the duration of the activity; rather, the budgeted units will be spread as follows: Week 1 – 10hours, Week 2 -30 hours, Week 3 – 15 hours, Week 4 – 25 hours. By manually entering the planned resource/role distribution in future period assignment buckets, you can create an accurate baseline plan to measure against current project progress. As the current project schedule progresses and you apply actuals, you can track how the project is performing against plan by comparing the project’s budgeted future periods to the current project’s actuals.

If work on an activity is not proceeding according to plan, you can manually update the remaining units for an assignment's future periods, enabling you to measure the remaining work for an assignment without changing the original plan. Alternatively, if you choose to re-estimate future work based on changes to the project schedule, you can edit an assignment's future period budgeted units while the activity is in progress; if many assignment's require re-estimation, you can establish a new baseline plan based on your changes.


• You can compare the planned future period resource distribution to actual units and costs in the Resource Usage Profile, Resource Usage Spreadsheet, Activity Usage Profile, Activity Usage Spreadsheet, time-distributed reports, and the Tracking window. If you plan your project work in defined financial periods, after you store period performance, you can compare the resource distribution you planned to the project's past period actuals.

• Activity costs, including earned value and planned value, are calculated using the planned future period resource distribution you define for activity assignments.

Note : You must have the 'Edit Future Periods' project privilege to manually enter future period data.

Key Terms -

Level 1 Schedule – Reflects management summary for overall/total time frame & scope of project highlighting contractual and Project milestones.

Summary Schedule – The level of schedule by facility, discipline and areas for Engineering, highlighting long lead items, critical items for Procurement, and summarised by work package for Construction to depicts the relationship between facilities/phases and establish facility criticality.

Baseline Schedule – Originated from Contract Schedule and updated with agreed changes over the period of time for effective project progress monitoring/tracking.

Current Schedule – Originated from Baseline Schedule and updated with periodic progress and changes to reflect the current/actual status of the project.

Contract Schedule - Contractually agreed schedule for the defined scope and time offering reference points against which actual progress/status can be measured.

Original (Control) Budget - Contractually agreed man-hours/cost for the defined scope and time.