Framework for PERT and CPM

The Framework for PERT and CPM


Fundamentally, there are six steps which are common for both the techniques. The process is given below:

  1. Describe the Project and all its significant activities or tasks. The Project (made up of several tasks) must have only a sole start activity and a single finish activity.
  2. Create the relationships between the activities. Select which activities must precede and which have to follow others.
  3. Sketch the "Network" linking all the activities. Every Activity must have unique event numbers. Dummy arrows are utilized where required to ignore giving the same number to two activities.
  4. Allocate time and/or cost estimates to all activities.
  5. Calculate the longest time path by the network. This is known as critical path.
  6. Make use of the Network to make plan, schedule, and control and monitor the project.

The Key Concept employed by CPM/PERT is that a small set of actions or activities, which make up the longest path by the activity network control the whole project. If these "critical" activities could be recognized and allocated to responsible persons, management resources could be optimally utilized by focusing on the few activities which decide the fate of the whole project.

Non-critical activities can be re-scheduled, re-planned and resources for them can be re-allotted flexibly, without disturbing the entire project.

Five helpful questions to ask while preparing an activity network are:

  • Is this a Start Activity?
  • What Activity Follows this?
  • Is this a Finish Activity?
  • What Activity Precedes this?
  • What Activity is Concurrent with this?
