Theory of Constraints — A Concise, Expert Management Briefing

Project durations reduced by 25% to 50% On-time project completions in the high 90% range 100% to 200% more projects completed by the same resources in the same time

Critical Chain Project Management

In most project environments, people are working flat-out or even at burn-out rates. Uncertainty is characteristic of the environment; requirements, tasks, resource availability often change within the project life-span. Task times are estimates and can "prove" to be wrong by a mile.

In these circumstances it is difficult to understand how any approach to Project Management — not just Theory of Constraints — can claim to offer the potential for reduced project durations with high confidence levels in meeting the promised dates without compromising the deliverable or the project budget.

Yet that is exactly what the Critical Chain approach has been delivering in environments as far apart as IT projects, new product development, aircraft turnaround, road and building construction ... and many more widely varying project environments.

The Symptoms of the problem:

Planned project durations are longer than anyone would prefer.
Actual completion is typically later than the plans called for – often much later.
Projects are regularly over-budget by their completion.
The deliverable is often compromised to deal with lead time or budget pressures.
There is an end-of-project "crunch," often with major impact on resources and their subsequent productivity.
There is poor quality-of-life among project resources in general.

Common management frustrations:

"How can we ALWAYS be late? Once or twice I can understand, but why is it ALWAYS that way? Even when everyone always pads their part of the schedule, and WE add a buffer on top of that?"
"I can understand missing one deadline for a project, because there are a lot of unknowns ... but how come EVERY promised date after that is also missed? Even the ones that we get when the project is supposed to be 70% or even 90% complete? Aren’t we supposed to be experts at this?"
"Why do we always find out too late that the project is going to be late? If we’d known earlier we could have done some damage control or put more resources on it ..."
"Sometimes it seems to me that when we throw more resources at the project, progress seems to slow down not speed up!"
"We spend months, even years, hire the best people and invest a fortune to get the new product out ... then instead of capturing the planned market share we actually alienate many of the customers our sales and marketing people have worked for months to win, by promising dates we miss again and again and again ... "
"To get the thing finished even close to when we promised it we have to take resources away from other projects, and all we’re doing is digging our grave deeper with each one."

The Theory of Constraints Solution: Critical Chain Project Management

Project planned durations are reduced by 25% the first time the technique is used; then shrink more on subsequent projects as lessons are learned.
85 – 99% of projects actually being completed on or before the promised date – despite many Murphy-strikes, despite the uncertainties associated with projects in almost all environments.
The combination of the two above outcomes translates to projects actually being completed in a LOT less time than conventionally managed projects; not just 25% less.
Projects arrive on-budget, or very close.
Projects completed to original specification.
Above levels of performance typically without the characteristics that lead to burn-out – less overtime, more stable priorities, "crunch" episodes reduced in frequency and magnitude.
True Project status is clear at any time.
Basis for meaningful management what-if analysis before and during the project.
The Project Schedule typically remains stable for the duration of the project … despite all the realities that are so different from the expectations.

How is Critical Chain different from Critical Path?

The best way to describe the mechanical difference is in terms of outcomes. If you were to compare the Critical Path identified by Microsoft Project for a project and compare it to the project’s Critical Chain, you would notice two things:

1. The series of tasks that comprise the Critical Chain genuinely represent the longest path through the project network, taking into account task and resource dependencies, i.e. these are the tasks that genuinely deserve management’s rigorous attention.
2. Many of the tasks on that Critical Chain (sometimes "most," sometimes "all") do not appear on the Critical Path. Critical Path ignores resoutrce dependencies.

The difference is often major. However, the differences between the Critical Chain approach to Project Management and the Critical Path approach are far greater than just the difference in the focal point of the network of tasks; they include mechanical issues, policy and measurement issues, and most important of all – behavioral issues.