One of the most popular uses of networks is for project analysis. Such projects as the construction of a building, the development of a drug, or the installation of a computer system can be represented as networks. These networks illustrate the way in which the parts of the project are organized, and they can be used to determine the time duration of the projects. The network techniques that are used for project analysis are CPM and PERT. CPM stands for critical path method , and PERT is an acronym for project evaluation and review technique . These two techniques are very similar.
There were originally two primary differences between CPM and PERT. With CPM, a single, or deterministic, estimate for activity time was used, whereas with PERT probabilistic time estimates were employed. The other difference was related to the mechanics of drawing the project network. In PERT, activities were represented as arcs, or arrowed lines, between two nodes, or circles, whereas in CPM, activities were represented as the nodes or circles. However, these were minor differences, and over time CPM and PERT have been effectively merged into a single technique, conventionally referred to as simply CPM/PERT.
CPM and PERT were developed at approximately the same time (although independently) during the late 1950s. The fact that they have already been so frequently and widely applied attests to their value as management science techniques.