PERT 21: Fitting PERT/CPM for use in the 21st century

More than half a century after the debut of CPM and PERT, we still lack a project scheduling system with calibrated and validated distributions and without requiring complex user input. Modern decision support systems (DSS) for project management are more sophisticated and comprehensive than PERT/CPM. Nonetheless, in terms of stochastic analysis, they show insufficient progress. PERT 21 offers a radically different stochastic analysis for projects, based on relevant and validated theory. Operationally, it is sophisticated yet simple to use. It is designed to enhance existing DSS, and thus it can be implemented without sacrificing the investment already made in project management systems. Finally, regarding the important sequencing and crashing models developed under CPM, PERT 21 permits their adaptation to stochastic reality.

► Bidding for a new project, scheduling and control require reliable estimates.
► Reality is stochastic, but PERT's stochastic analysis “engine” cannot be validated.
► Risk analysis modules are usually based on subjective input, which is unreliable.
► We propose a new stochastic analysis engine, which was validated by field data.
► We also present graphical aids for planning and control of stochastic activities.