Trending in CPM—An Outline for Development of a Recommended Practice

摘要

The use of CPM (or the Critical Path Method) for calculation of a schedule from a baselineplan, and re-calculation of that schedule based upon past performance against that plan, has alwaysbeen limited by the power of current computer hardware. As the power of computer processors hasincreased and the cost of computer memory decreased over the years, many improvements theorizedat one time or another since CPM’s initial development in the mid-1950’s have been implemented.Examples include the development of PDM (Precedence Diagramming Method) from its originaldescription as a “non-computerized improvement” to the predominant format of CPM softwareproducts, RDM (Relationship Diagramming Method) introduced by Plotnick in 2004 and implementedin Primavera (now Oracle) Pertmaster (now Risk Manager) software in 2005, and Monte Carlosimulation for risk analysis as an improvement over PERT’s famous (O+4M+P)/6 formula. Currentlevels of computer “power” may now also consider the question of schedule forecasting based uponpast trends. It is the purpose of this paper to set forth an outline for development of an AACEInternational Recommended Practice on this topic.