The Completion Time of PERT Networks

PERT and critical path techniques have exceptionally wide applications. These techniques and their applications have contributed significantly to better planning, control, and general organization of many programs. This paper is concerned with a technical improvement in PERT methodology by introducing a new approach to approximating, in a computationally efficient way, the total duration distribution function of a program. It is assumed that the activity durations are independent random variables and have a finite range. The first part of the paper considers PERT networks and deals with the lower bound approximation to the total duration distribution function of the program. Then we use this approximation and CPM to propose bounds for the different moments of the distribution function. We illustrate this with numerical examples. In the second part of the paper we adapt our results to PERT decision networks.