Superpath: A Non-Computerized Probabilistic Scheduling Methodology Using First Principles of the U. S. Navy's Program Evaluation Review Technique
Smith, Charles Christopher
Baecher, Greg B
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The Superpath method, a non-computerized probabilistic scheduling methodology relying upon first principles of the Program Evaluation Review Technique (PERT) and a summary level, event-centric network is presented. Like PERT, a network scheduling methodology developed by the United States Navy during the development of the Polaris submarine launched ballistic missile program of the 1950s, Superpath employs probabilistic techniques within a network-based time management platform allowing for the assessment of program or project performance against calendar dates certain. The proposed methodology relies upon the identification of easily identifiable, distinguishable, unambiguous and measureable events along with either short term probabilistic or deterministic time estimates for the single summary paths, or Superpaths, that lie between. A fundamental tenet of the Superpath approach is that the topology of several key events or reference points in time, vice hundreds or thousands of activities, forms a valid basis from which to perform a schedule analysis. Once this simplified network is constructed, conventional deterministic calculations are performed to determine the slack along each Superpath affording the capability of evaluating the probability of the project's on-time completion. Superpath also accommodates the nearness of non-critical superpaths, a limitation of PERT and modern-day CPM. Superpath differs from the Critical Path Method (CPM), perhaps the most common network scheduling methodology as of 2008 and widely employed within the projects and programs of public and private industry. CPM is a network based methodology that relies upon a relatively large number of work activities and multiple types of network relationships as the basic network. CPM is task focused whereas Superpath focuses on discrete events and considers the interstitial space between events in far less detail. Complex relationships, sequential activities, "logic lags," constraints, calendars and the daily unit of measure are also aspects of CPM not found in Superpath. Generally, probabilistic analysis of time is not part of a CPM methodology, which relies upon a deterministic treatment of time using a single estimated durations for each activity.