An R&D leader recently asked me for a crisp and succinct explanation of the differences between Critical Chain (CCPM) and Critical Path project management.
There are many differences and some are subtle, but if I had to boil it down to a single sentence, it would be:
CCPM is built for flow so that you can run projects like a relay race.
If I were allowed to go a level deeper, I’d explain that there are three key differences:
1. Eliminating Planned Multitasking:
- Critical path planning is based solely on task dependencies meaning that a resource can be scheduled to work on more than one task at a time.
- Critical chain eliminates planned multitasking by considering resource dependencies in addition to the traditional task dependencies.
2. Buffering for Variability:
- Critical path embeds safety in every task where it enables and encourages procrastination and does little to protect against variability.
- Critical chain tasks include only the actual work effort and the due date is protected by a shared project buffer.
3. Relay Racer Execution:
- The tasks in a critical path plan are each worked to a due date so with normal procrastination early task finishes rarely result in an earlier project finish.
- The tasks in a critical chain plan are worked like a relay race with each runner focusing on finishing their leg of the relay and handing it off to the next runner as soon as possible.
Of course, the biggest difference of all is in the results – Because CCPM projects have a much higher chance of finishing on time (90% +) and in 25-50% less time!
