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 extensive
stages in the current enhancement to the Project Management Body of knowledge.
The chief difference between the critical chain and the critical path is the
inclusion of resource dependencies. The critical chain project management
improves the project plan by guaranteeing that it is feasible and protected
from rational common cause variation or any uncertainties and this is done by
including buffers at the end of activity paths. The inclusion of buffer ensures
the protection of the complete project completion on the critical chain path
and the critical chain is kept from path merging by feeding buffers.
Measurement and decision making is improved and better project control is
achieved from buffer management. The exclusion of data driven activity
performance and multitasking and other changes in resource behavior were
necessary for implementation of Critical chain project management. The cost and
schedule records were improved in projects that used CCPM. The projects using
other planning methods took twice the time to complete when compared to
critical chain project management.
Critical chain project management was developed from the
theory of constraints. The change and uncertainty in duration of activity is
directly addressed by Critical path project management planning and control
process. Overall duration of the project is reduced by development and
management of project performance to meet or to exceed reduced activity times.
Wafers of semiconducting material were produced by a company
named Haris semiconductor. 8″ wafer plant was built using critical chain
project management. 250 million dollars were invested for the wafer plant. 2
million dollars per day was the revenue from such a plant as the cost of the
raw material is low. It took the company thirty months to build a new wafer
plant of 6″. It took 46 months to start the plant to run to ninety percent of
its capacity. Haris took fourteen months to build the plant and bring it up to
production of ninety percent capacity, their results were presented at a
conference that was hosted by AVARAHM Y GOLDRATT institute.