Graphical Path Method, Papers

In this paper, presented at the 2009 PMI College of Scheduling Conference, PMA Consultants’s Dr. Gui Ponce de Leon addresses the methodology and logic behind the Graphical Path Method (GPM) and how the emergence of the GPM application will inevitably change the project management process going forward.


CPM (Critical Path Method) applications anchored on database-driven scheduling engines controlled via keyboard and mouse have been the dominant paradigm in project management. Database modeling of what is arguably a graphical application in akin to CAD – on like support until 3D Modeling/BIM pulls the plug. While CPM software vendors seem to be focused on complex scheduling engines, intuitive graphical user interfaces anchored on objectbase principles and gestural computing are progressing to where they are ignored at the user’s risk.

Historical Context

Owing to the technology of the times, early CPM practice was graphical and planning-centric. A “CPM” was a graphically-depicted project network (whether hand-drawn or computer-drawn) conveying activities and logic, ergo the “plan.” Dates and floats were simply the mathematical corollary of the network graph. The motto was: logic rules, dates serve. Scheduling was an above-board exercise; what with the network model for all to see. Manipulation of a schedule was not a consideration – else the manipulator might expose himself to ridicule.

Starting in the mid-1980’s, with the computational power of the PC, the practice of CPM morphed into a data driven paradigm – sans the graphics. The power of the graphics was supplanted by the sophistication of the scheduling engine. Without a graph for all to see, eventually it became: dates rule, logic serves. The end game was to get the dates by crook & hook, logic was secondary. Two generations of schedulers have grown to believe that network anomalies such as endless constraint dates, negative lags, retained logic/progress override, loose ends, activities with only start-to-start or finish-to-finish successors, et. al., were tools of the trade. A “CPM” went from a network diagram to software-driven activity and logic data, conveyed by a listing and/or a bar chart to boot!

At some point, the elders of the scheduling community cried out: we are not going to take it any more. There being far more entrenched stakeholders (i.e., software vendors and present-day schedulers) than elders, no change was effected. Arguably, the scheduling profession remains mired in the morass in which it has been for the last two decades. Except, courtesy of new, powerful graphics interfaces, new thinking and the foundational power of the mathematics underlying network graph theory, help is on the way.

The Graphical Planning Method® (GPM)

GPM transforms conventional CPM planning and scheduling by making it an engaging, interactive, realtime process anchored in computerized, graphical, objectbase project networking methods. The intent is for GPM software applications to hinge on GPM algorithms for object encapsulation and message passing. Existing CPM applications rely on inline CPM scheduling engines to process data to carry out schedule calculations in a succession of batch modes. In contrast, GPM applications rely on objects that contain embedded rules and computational algorithms that interact with one another via message passing to perform planning and scheduling functions in real time – in addition to interactive graphics display.

Authored By:

Dr. Gui Ponce de Leon, PE, PMP, LEED AP
Originally published as a part of PMICOS 2009 Annual Conference

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