Critical Chain Project Management

Critical Chain Project Management (CCPM) was first introduced by Eliyahu Goldratt in the late 1990’s.  It is a descendent of Goldratt’s earlier theory entitled Theory of Constraints (TOC).  TOC was designed to simplify the approach to addressing overall system or project deficiencies.  It suggests focusing on the actual processes within the system that are causing the deficiencies – the constraints – instead of the entire system.

With CCPM, Goldratt took his theory one step further and demonstrates how modifications in both the planning of a project and the priority of work-flow for the project team can reduce production times.  It is important to point out that CCPM focused mainly on reducing production time as opposed to cost reduction.  Though CCPM was used successfully for several years after Goldratt’s introduction, its use became obsolete in early 2000 when the economy forced most businesses to direct their resources towards cost saving techniques.

Project Management is a fine balance of three essential variables: time, resources and scope.  Changes to any one of these variables will have an effect on the other two and, in turn, will impact the project overall.  Critical Chain Project Management addresses the specific variable of time within a project and how to best plan to eliminate drawn out or late project completions.  More importantly, CCPM shifts the focus away from individual task completion dates and on to the ultimate goal of the project – the due date. 

CCPM in regards to a single project requires two main behavior changes in the members of the project team.  When developing the project schedule, every good project manager will allow for buffers for unexpected delays, or “Murphy Laws.” 

 Unfortunately, these buffers are often exaggerated, taken advantage of, or pushed to their limits.  Goldratt refers to this as “student syndrome.” Instead of starting tasks as soon as they are passed, some workers hold off on starting for various reasons: not ready, too busy, have plenty of time.  This eats away the buffer time allowed and leaves the team at higher risk of late completion in the event of a later delay.  CCPM calls for all tasks to begin immediately following the completion of the preceding task.  To assist in establishing this flow of work, the Project Manager should consult each task group during the planning phase and ask that their buffer time be identified.  In other words, “How much lead time will you need to be ready to start YOUR task?”  As each task enters completion, and based on the following task’s buffer requirements, the project manager will provide alerts to the task group to anticipate beginning their task, otherwise known as countdowns.  This will provide for smooth work-flow from one task to the next with little to no pause in production.

The second behavioral change needed is what is often referred to as “Parkinson’s Law” defined as the work expanding to fill the time available.  Some task members are reluctant to pass on their completed work to the next task if they complete their work ahead of schedule.  There is a universal fear that if less time is used than was allotted, than future projects may assign less time to them for their task.  It is important that all task members understand that the key to achieving the project due date is that each task begins immediately and not necessarily according to the project schedule dates. An excellent analogy used for this process as used by Richard E. Zuther in his article Getting Projects out of your System; a Critical Chain Primer is to picture relay runners in a race.  They are in a resting position as they wait for the baton. When they are passed the baton, they are ready to run at full speed.  When they pass the baton, they then rest again.  Goldratt’s entire theory is based on reducing workload and lowering individual utilization to achieve greater project throughput.

Additionally, a CCPM project manager needs to allow for the exaggerated figures received from most members of the project.  When creating the project schedule, CCPM suggests cutting each time line by 50% and then allowing for some of this time in buffers.  It is not suggested that task members work twice as fast.  If the CCPM format is followed, and each member works immediately on their project with 100% effort, the full time predicted time frame will not be needed.  Any delays or “Murphy Laws” that arise will be handled with the buffer time allotted.

Critical Chain Project Management in regards to multiple projects employs the same concepts as the single project approach but also addresses the inefficiency of multitasking.  By using resources to complete all tasks on a single project before moving on to another, project completion is shortened.  This also allows for a few days in between projects for resources to rest, again employing the relay runner philosophy discussed earlier.

Though multitasking appears to be the most efficient approach, it actual slows production time since resources are trying to complete multiple tasks simultaneously.  It also can have a detrimental effect on quality since switching back and forth between tasks leaves more room for error.  Reducing the use of your resources from 100% to 80% will increase your overall quality and speed on individual tasks. 

Though Critical Chain Project Management has been around since the late 1990’s, it is not well known in today’s Project Management forums.  This is primarily due to businesses being forced by the economy to focus on increasing revenue instead of improving project throughput. However, project management professionals familiar with CCPM strongly believe that the value of this technique will be re-discovered as the economy begins to improve.