The program evaluation and review technique ( PERT),”(also called PERT/CPM) uses the project network diagramming technique to create a visual repre-sentation of the scheduled activities that expresses both their logical sequence and interrelationships. It also uses a statistical distribution that provides probability for estimating when the project and its associated activities will be completed. This probabilistic estimate is derived by using three estimates for each activity: optimistic, most likely
and pessimistic.”