Critical chain project management

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Critical chain project management (CCPM), sometimes also critical chain multi -project management or rarely also critical chain management (CCM), is a project management method based on the ideas of Eliyahu M. Goldratt .

CCPM expands classic project management by the two elements avoidance of harmful multitasking and correct handling of estimates, their scatter and associated buffers .

Project approval and staggering

The harmful multitasking is avoided by limiting the number of projects to a reasonable level and then, depending on the limiting resource, released (project release) and clearly prioritized (graduation). In contrast to the critical path method, real available resources are used here and planned strictly according to priority; the longest path, based on resource consumption, is referred to as the critical chain . This staggering is known as strategic prioritization .

This prevents a resource from working on several work packages at the same time and switching between them (harmful multitasking). The result is that the available resources can work in an optimally concentrated manner on a work package and the throughput times are massively reduced.

Buffer management

The correct handling of estimates is based on accepting the unavoidable scatter and using the associated buffers in the sense of the project (buffer management).

Psychology of the buffer

In a classic corporate environment, the employee typically estimates the effort and thus the duration of a work package including a buffer to increase their own reliability. Due to Parkinson's law that says buffers are always used and not cut, Student Syndrome , which says to start as late as possible, and combined with Murphy's law , which says that something always goes wrong, prematurity won't happen and delays always passed on.

Project buffer

In the CCPM, estimates are therefore chosen for the individual work packages in such a way that they will arrive with an absolute probability of approx. 50%. The difference to the classic estimate is provided as a joint project buffer for all work packages at the end of the project. In this way, early and late payments can be compensated for, which in turn is used to reduce this buffer by 50%. The result is a very high adherence to delivery dates combined with a 25% reduction in throughput time.

Project progress according to CCPM - progress compared to buffer consumption

Operational prioritization

In multi-project environments, the situation often arises that several work packages from different projects are pending for processing by one resource. In this case, the resource must decide which work package is processed with priority. This staggering is known as operational prioritization .

The work package of the project with the worst ratio of progress to buffer consumption on the critical chain is always preferred.

The key figures progress on the critical chain and buffer consumption can also be viewed over the duration of the project or over the entire project portfolio, in order to identify projects that are in imbalance and to take measures (traffic light control).

Management culture

As a rule, a change in management culture must be associated with the CCPM.

Employees must be assured that they will not face reprisals even if the estimates are exceeded or not reached. The superiors must prioritize the necessary projects and prevent multitasking for the individual project employees.

This cultural change is typically accompanied by a reduction in overtime, easier and more fluid work, mutual support, higher quality and motivation, followed by greater innovative strength.

literature

  • Eliyahu Goldratt: Critical Chain. North River Press, Great Barrington 1997, ISBN 0-88427-153-6 .
  • Uwe Techt, Holger Lörz: Critical Chain - Accelerate your project management. Haufe-Verlag, 2011, ISBN 3-648-01251-7 .
  • Lawrence P. Leach: Critical Chain Project Management. Artech House Publishers, ISBN 1-58053-074-5 .

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