Programme Evaluation and Review Techniques (PERT) & Critical Path Method (CPM) August 20-25, 2001

Abstract

This paper by Dr. K.K Bandyopadhyay examines Programme Evaluation and Review Technique (PERT) and Critical Path Method (CPM) as project management techniques for planning, scheduling, and controlling projects and helps in determining project duration, identifying critical activities, and managing flexibility in scheduling. The paper traces the historical development of both techniques, noting that PERT was developed in the United States during the 1950s to plan and accelerate ballistic missile development, while CPM was developed independently and focuses on obtaining trade-offs between cost and completion date. It introduces key terminologies for an in-depth understanding of PERT and CPM through an example of the budgeting process of an organization called DEEP, demonstrating how projects are broken down into jobs with immediate predecessor relationships and time estimates. Activity-on-node (AON) diagrams are used to portray these relationships graphically. The paper also explains how PERT calculates the expected value of activity duration as a weighted average and provides a formula for it. Further, it examines the concept of the critical path, or the longest path of the network project, arguing that its length determines the duration of a project and must be shortened to reduce project completion time. It analyses concepts like job slack and presents an algorithm for finding the Critical path. The paper concludes by demonstrating an example of a watershed project to identify the critical path.