Program and Project Critical Paths

When an IMS is constructed from multiple projects, two levels of critical paths need to be managed: the overall IMS critical path and the project critical paths. When an IMS is created from several projects, the IMS-level critical path may or may not contain the same activities as those driving individual projects. The program critical path may be made of different sequences representing how each project ties into the overall program effort. However, it is expected that the program critical path will contain one project’s critical path because there will be at least one project driving the overall program length.

The program critical path will change every month as work is updated and some activities are finished early and others late. Both levels of critical paths should be monitored because a failure in one project critical path can cause that project to become part of the program critical path at any time.

The management of a program-level IMS created from many projects can become daunting and highly complex, especially if software limitations prevent schedulers from easily tracking each critical path through thousands of detail activities. If the benefits of monitoring a program-level critical path through detail project activities are minimal compared to the effort required, then intermediate schedules may be used to represent some projects. As we saw in Best Practice 1, intermediate schedules are linked to lower-level detailed schedules and may or may not include detailed work activities. Projects that are an integral part of the program and contribute to the overall critical path should have their detail activities broken out. Projects that are relatively independent from the overall program duration will have their own critical paths and can be shown as summary tasks in the intermediate schedule.