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project buffer

См.: буфер проекта.



project buffer

project buffer - A time buffer placed at the end of a project to protect against variation in the time it takes to complete tasks on the critical chain.

Usage: The project buffer is not formed by simply adding time to the end of the existing project network. Rather, safety time is removed from individual task time estimates of the activities on the critical chain. Half of this removed safety time is placed strategically at the end of the critical chain in a project schedule to protect the overall schedule. The project buffer will be penetrated, or depleted, when tasks on the critical chain take longer than estimated or after a feeding buffer has been used up and there is still time required to complete some task(s) on the associated non-critical chain. A rule of thumb is that the project buffer is one-half the length of the critical chain thus making the project buffer one third of the total project duration.

Perspective: In critical chain project management, 50% task time estimates are used to determine the length of the critical chain and the project buffer is established at just 50% of the length of the critical chain. This buffer size represents only one half of the contingency or safety time removed from the individual task estimates. The combination of using 50% task time estimates and a project buffer that is 50% of the length of the critical chain reduces the estimated duration of the overall project by approximately 25% of what it would have been under traditional project management, while at the same time providing a visible buffer for use by management to protect the project.

Syn.:completion buffer.

See:50% task time estimate, buffer, critical chain, feeding buffer.