What is the background of CPM and PERT? What are the differences between the two techniques?

Question

What will be an ideal response?

Answer 1

PERT and CPM are the two primary methods for developing activity networks. PERT, which stands for Program Evaluation and Review Technique, was developed in the late 1950s in collaboration between the U.S. Navy, Booz-Allen Hamilton, and Lockheed Corporation for the creation of the Polaris missile program. PERT originally was used in research and development (R&D), a field in which activity duration estimates can be difficult to make, and resulted from probability analysis. CPM, or Critical Path Method, was developed independently at the same time as PERT by DuPont, Inc. CPM, used commonly in the construction industry, differs from PERT primarily in the assumptions it makes about estimating activity durations. CPM assumes that durations are more deterministic; that is, they are easier to ascertain and can be assigned to activities with greater confidence. Further, CPM was designed to better link (and therefore control) project activity time and costs, particularly the time/cost trade-offs that lead to crashing decisions (speeding up the project). In practice, however, over the years the differences between PERT and CPM have blurred to the point where it is now common to simply refer to these networking techniques as PERT/CPM.