3. History - Goldratt’s Critical Chain
Critical Chain Project Management (CCPM) is a methodology
for planning, executing and managing projects in single and multi-
project environments, that puts the main emphasis on the resources
required to execute project tasks.
Critical Chain Project Management was developed by Dr Eli Goldratt
and was first introduced to the market in his Theory of Constraints book
“Critical Chain’ in 1997.
It was developed in response to many projects being dogged by poor
performance manifested in longer than expected durations, frequently
missed deadlines, increased costs in excess of budget, and substantially
less deliverables than originally promised.
Goldratt. E.M. (1997), Critical Chain. United Kingdom: Avebury. ISBN-10: 0566080389
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4. History - Goldratt’s Critical Chain
This is in contrast to the more traditional CPM and PERT methods,
which emphasise task order and rigid scheduling.
A Critical Chain project network will tend to keep the resources levelly
loaded, but will require them to be flexible in their start times and to
quickly switch between tasks and task chains to keep the whole project
on schedule.
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5. THE
Problems BA SI C S
• Project failure - some causes
– Not starting the task until the last moment
• (Student Syndrome)
– Delaying (or pacing) completion of the task
• (Parkinson’s Law)
– Cherry picking tasks
– Management forces
6. THE
Critical Chain Project Management (1) BA SI C S
Addresses these issues in the following ways:
Planning
Critical Chain - longest chain (not Path) of dependent tasks
Estimations - recommends that task estimates are cut to half
the length of a “normal” duration
Safety - ‘Buffers’ manage the impact of variation and
uncertainty
Project Buffer
Feeding Buffer
Resources Buffer
7. THE
Critical Chain Project Management (2) BA SI C S
Execution
Priorities - all project resources are given clear and aligned
priorities relating to the ’health’ of the chain, and related to its
associated buffer
Completion - ‘Roadrunner’ approach - when there is work
available it should be progressed at the fastest possible speed
(with compromising quality) until completed
Review
Buffer Management - amount of each buffer consumed
indicates how the delay could effect project completion
Remaining Duration - tasks are monitored on their
remaining duration, not their percentage complete.