PROGRAM EVALUATION AND REVIEW TECHNIQUE (Problems Eventually Resolve Themselves)

This paper will go through the rudiments of PERT. Warning - PERT is not for everyone, nor is it intended for use on all projects. Therefore the schedulers should use PERT with extreme caution. PERT is a statistical technique applied to a network schedule. PERT was an outgrowth from Set Back charts used in Line of Balance methodology

(remember the U.S. Navy had a large size oar in the establishment of LoB) and CPM.

RESOURCE LEVELING

In the Government contracting environment the first attempt at resource leveling generally is accomplished during the proposal preparation phase. Unfortunately this is also the last time it is attempted.

If the customer asked for, by contract clause, a full CPM/PERT schedule to be monitored, status, and reported against and a validated application of the C/SC (Cost/Schedule Control) system to the project - resign - you are faced with a dilemma trying to accomplish both requirements. Here's why:

• C/SC brings a requirements for a firm fixed baseline changeable only by formal work scope change.
• CPM and/or PERT require a moving schedule to properly status, and monitor key milestone dates and accurately predict key completion dates.
• In order to satisfy both management techniques a dominate - subordinate order should be selected. If it is not selected, then during the evolution of the project; one of the two methods will become dominant. You cannot correctly manage a project with two sets of baselines.

SCHEDULE BASELINE DEVELOPMENT

1. Define General Scope
2. Develop Master Schedule
3. Develop Detailed Scope
4. Assign Responsibility to Individual Activities
5. Develop Detailed Network Logic
6. Establish Activity Durations and Lead Times
7. Solve CPM Logic to Determine Start vs. Complete Dates
8. Verify Consistency of Schedule at Different Levels and Revise Logic if Necessary
9. Load Resources at Activity Level
10. Make CPM Schedule with No Resources or End Date Restrictions
11. Define Priorities for Resource Leveling
12. Resource Level Schedule
13. Team Review of CPM for:
• Inclusion of All Work Products
• Responsibility Assignments
• Logic Restraints
• Resource Plan Practicality
14. Revise as Necessary

15. Approve Schedule Baseline

SCHEDULE BASELINE REVISIONS

The Approved Baseline Schedule should be revised only:

1. When approved scope changes impact the schedule
2. If Project is delayed or accelerated or other customer direction is received.
3. When unrecoverable slippage has occurred (this example is the least desirable and the one which should be used with the greatest caution).

A conflict which invariably exists and is difficult to resolve is how to measure schedule status. For network analysis to be useful, it must always reflect the latest available information. On the other hand, "latest status" varies each reposing period, and it is not possible to do meaningful trending against a constantly changing target.

The key to resolving this dilemma is to understand the difference between status and performance determination. A CPM network can and should be used to provide current status information and forecast completion dates of all future key milestones. However, it should not be used for measuring schedule performance. For schedule performance to have any meaning, it must be measured against a set technical baseline plan.

DIRECTED DATE

A directed date is a specified date which is frozen in the schedule. "Not earlier than" means that an activity can start no earlier than the specified date, even if the network solution would allow it to start earlier. This type of directed dates supersedes the network solution on the forward pass only. Directed dates are normally specified by the customer, Senior Corporate Management, the Project Manager, or the Functional Manager. Directed dates normally result from the desire to integrate selected items both internally and externally to the project.

This discussion does not mean to imply that direct dates have no valid application. Any major milestones which must be fixed should have imposed target dates. This will also help assure schedule consistency for traceable milestones on successive reports. But there are other valid reasons for using directed dates besides using them to freezes major milestones. In come cases, a not later than date should be imposed to assure that the activity is accomplished during the necessary time frame.

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