Chapter 22 is the key to understanding the critical chain method. Rather than scheduling projects based solely on the task of the critical path, project should also consider the constraints of resources working on multiple projects. How can new development projects at any construction firm account for “bottleneck” resources necessary to complete multiple projects? Critical Chain project management gives us with extensivestages in the current enhancement to the Project Management Body of knowledge.
The chief difference between the critical chain and the critical path is theinclusion of resource dependencies. The critical chain project managementimproves the project plan by guaranteeing that it is feasible and protectedfrom rational common cause variation or any uncertainties and this is done byincluding buffers at the end of activity paths. The inclusion of buffer ensuresthe protection of the complete project completion on the critical chain pathand the critical chain is kept from path merging by feeding buffers.
Measurement and decision making is improved and better project control isachieved from buffer management. The exclusion of data driven activityperformance and multitasking and other changes in resource behavior werenecessary for implementation of Critical chain project management. The cost andschedule records were improved in projects that used CCPM. The projects usingother planning methods took twice the time to complete when compared tocritical chain project management.Critical chain project management was developed from thetheory of constraints. The change and uncertainty in duration of activity isdirectly addressed by Critical path project management planning and controlprocess.
Overall duration of the project is reduced by development andmanagement of project performance to meet or to exceed reduced activity times. For example,Wafers of semiconducting material were produced by a companynamed Haris semiconductor. 8″ wafer plant was built using critical chainproject management. 250 million dollars were invested for the wafer plant. 2million dollars per day was the revenue from such a plant as the cost of theraw material is low. It took the company thirty months to build a new waferplant of 6″.
It took 46 months to start the plant to run to ninety percent ofits capacity. Haris took fourteen months to build the plant and bring it up toproduction of ninety percent capacity, their results were presented at aconference that was hosted by AVARAHM Y GOLDRATT institute.