PERT, CPM and the Tangled History of Network Scheduling

Authors

• Charles Christopher Smith, Ankura Consulting GroupFollow
• Vivek Sharma, Clemson UniversityFollow
• Gregory B. Baecher, University of MarylandFollow

Abstract

The origins of two network scheduling techniques: The Program Evaluation Review Technique (PERT); and the Critical Path Method (CPM) are examined. Prior accounts hold that each are different and were created separately. PERT, developed within the U. S. Navy’s highly classified POLARIS nuclear missile program which began in 1955. CPM, the creation of American industrial concerns E. I. du Pont de Nemours (du Pont) and Remington Rand UNIVAC. With the objective of settling “an acrimonious dispute over parentage,” this research examines the literature and the original forms of PERT and CPM noting their ‘dead ring’ resemblances, synchronous development timelines, while introducing personal and corporate proximities between the two research teams. This study supports the notion that CPM was derived from the U. S. Navy’s PERT system, and with only subtle differences, deliberately presented as an original concept to avoid the appearance of a leak from a highly classified nuclear missile program at the height of the Cold War. It also supports the possibility that CPM researchers played a role in the development of PERT. Regardless of which came first, PERT and CPM’s place in history is secure as practically identical computer applications employing theories, models and terminologies provided prior to 1955 by various contributors and researchers identified in this study.

Recommended Citation

Christopher Smith, Charles; Sharma, Vivek; and Baecher, Gregory B. (2020) "PERT, CPM and the Tangled History of Network Scheduling," The Professional Constructor: Vol. 45: No. 2, Article 6.
Available at: https://open.clemson.edu/aic-journal/vol45/iss2/6