Critical Chain Project Management
One of the novel concepts in the field of project management is that of critical chain project management (CCPM), a term that was invented in 1997 by the late Israeli physicist and business management guru Elijahu M. Goldratt.
In his book Critical Chain— which is written in the form, not of a how-to-guide, but of a work of fiction— Goldratt portrays people attempting to teach and implement the new theory. Incidentally, he also wrote several other books— including the Goal, It’s Not Luck, and Necessary but Not Sufficient— with the same format.
The critical chain may be defined as “the sequence of both precedence- and resource- dependent terminal elements that prevents a project from being completed in a shorter time, given finite resources.” The goal of CCPM, then, is to detect such terminal elements and develop a plan for either eliminating them altogether or, if this is not possible, for lessening the extent to which they interfere with things.
All forms of project management are, in the final analysis, aimed at minimizing the level of uncertainty associated with business activities. The goal of the project manager is to reconcile two conflicting aspects of projects with each other: the need for speedy project delivery on the one hand, and the need for reliability— that the promised goods will be delivered or services performed— on the other.
Critical chain project managers speak of “implicit” resource dependencies, which are to be identified through an examination of resource requirements, even though they are absent from the project list. It is the use of such dependencies, among other things, that distinguishes critical chain analysis from critical path analysis, a project- scheduling algorithm for which the former was developed largely as an alternative. Other differences include the use of buffers and allowing a “good enough” solution to be chosen, rather than the optimum one.
Critical Chain PD-Trak Project Management Software
Critical chain project management software is available from many dealers. One such company is PD-Trak Solutions, which offers the software as an add- on to Microsoft Project™. The user puts together a table outlining the details of each task— when it occurs in the sequence, its average duration (typically half of the safe estimate), its “safe duration,” and a bar graph that displays the beginning and ending dates when each resource will be used, and how they will come together. The user can also click on any of several boxes above the graph— Level resources, Calculate critical chain, Calc buffers, Insert buffers, Set baseline, and Show baseline. Choosing the first path resolves contention between or among resources. When “Calc critical chain” is clicked on, those events that figure into the chain are graphed in red (the rest are in violet). “Calc buffers” reveals the feeder and project buffers, which are shown in green and their relations to other resources indicated by arrows. These buffers can then be inserted into the timeline, and a baseline set.
PD-Trak software may also be used to track projects. Just below the boxes mentioned above are three menus for tracking, formatting, and filtering. Under the tracking menu can be chosen “update buffers” and “buffer report.” When the former is chosen, the colors of the buffers are changed to violet and red if they are now, respectively less than half and a quarter of their original value. Black lines are also added to indicate how close each buffer project is to completion.