View source for Critical Chain Theory

= History =
CCPM was developed by Eliyahu M. Goldratt and introduced in 1997 in his book, Critical Chain.<ref name=Goldratt> ''Goldratt, Eliyahu M. Critical chain. Great Barrington, MA: North River Press, 1997.'' </ref> Critical Chain Project Management is facilitated through algorithms and methods based on the principles of the Theory of Constraints.<ref name=GKRand /> The theory of Constraints is outlined in the following segment.

Proponents of CCPM have attested that the benefits over PERT and/or CRM is that application of the Theory of Constraints focuses on how upper management are handling human behavior while envisioning the project network and in managing it afterwards, in constrast to dealing solely with specific technical aspects as the before mentioned methods.<ref name=GKRand/>

=== Theory of Constraints ===
Theory of Constraints, noted TOC in the article, is a description of how repetitive production systems, with the factor that every system exhibits a certain constraint and overall system performance can only be enhanced by improving the performance of the particular resource constraining the system. The critical chain technique is the realizing component to the theoretical TOC.<ref name=Steyn1> ''Steyn, Herman. "An investigation into the fundamentals of critical chain project scheduling." International Journal of Project Management 19.6 (2001): 363-369.'' </ref> The Theory of Constraints is typically applied through five steps:<ref name=GKRand/>

# Identify the system's constraint(s).
# Decide how to exploit the system's constraint(s).
# Subordinate everything else to the above decision.
# Elevate the system's constraint(s). 
# If, in the previous steps, a constraint has been broken, go back to step 1, and do not allow inertia to cause a system's constraint.

A constraint in the system is a part that constrains the overall objetive of that system. A typical example is bottlenecks commonly found in production systems.<ref name=GKRand/>

The benefits of applying TOC varies from project to project. A review of the use in the industry show a clear positive effect for the companies involved. The results of 82 companies, ranging in size and industry, were aggregated and analysed. The results are shown in figure 2 and 3. Lead-Times, Cycle-Times and Inventory Levels were reduced by respectively 70%, 65% and 49%. Meanwhile were Due-Date-Performance, Revenue/Throughput and the Combined Financial Variable increased by respectively 44%, 63% and 76%.<ref name=Hallmark> ''Mabin, Victoria, J., and Steven J. Balderstone. The World of the Theory of Constraints: A Review of the International Literature. Boca Raton, FL: St. Lucie Press, 2000.'' </ref> The conclusion in this review was clear recommendation of TOC principles even applied to various degrees. Over 100 cases showed no failures or disappointing results.<ref name=Hallmark/>

{|style="margin: 0 auto;"
| [[File:CritChain_Industry_Increase.png|300px|upright|thumb| Figure 2 - Reported changes in operational and financial performance, resulting from the application of TOC. (More is better) <ref name=Hallmark/>]]
| [[File:CritChain_Industry_Decrease.png|300px|upright|thumb| Figure 3 - Reported changes in operational and financial performance, resulting from the application of TOC. (Less is better) <ref name=Hallmark/>]]
|}