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Differences Between
Critical Chain (CCPM) & Traditional Project Management

Page Contents

Summary Table
Summary Table of Differences between Critical Chain Project Management (CCPM)
and Traditional Project Management

Traditional Project Management Methods

Critical Chain Project Management (CCPM)

Benefits obtained from CCPM
1. Schedules worst-case task durations. Schedules average task durations. Task times do not collect safety time "fudge factors".  Risk, stress, and effort are shared equally amongst all tasks & resources.  People start to think differently than before.  "Sacred cow" schedules are avoided.  People can see what's really consuming the elapsed time.  Management can manage, project durations are cut, people can go faster with less stress.  Everybody and every resource are treated fairly & by the same rules.  Ineffective hierarchies are broken down.
2. Protects individual tasks with safety time. Protects overall project completion with buffers. Safety time is not hoarded by individual tasks and people, but shared by everyone.  Safety time is conserved and used most wisely over the entire project.  Focus is placed on what is most important to the customer: speedy deliverables.
3. Emphasizes task progress. Emphasizes project progress. Everybody sees the "Big Picture".  Micro-management is avoided.  Project Managers have a consistent outlook through the entire project.  Events that slow the project are constantly in the schedule spotlight.  People stay focused on the problems.  Problems get identified more quickly, and get solved sooner.
4. Starts gating tasks ASAP. Starts gating tasks when they need to start. Critical and limited resources are not plugged up with non-critical tasks which block & slow critical tasks.  This is similar to Fire Lanes and sirens on emergency vehicles.  Non-critical traffic stays off the roads until the emergency vehicles have passed.  Use of bottleneck resources is based on priority, not "first come, first served".  Projects get completed faster.
5. Starts and finishes tasks at scheduled start and finish times. Starts tasks as soon as predecessors are done, finishes tasks as quickly as possible.  Project is managed and implemented like a relay race.  The baton always goes around the track at maximum speed.  Runners pace themselves for hand-offs so the baton never stops nor slows down.  If you are carrying the baton, just finished carrying, or getting ready to carry it next, your activities are tightly monitored, controlled, and managed; all others are of lesser priority and have freedom to self-manage.  People focus better, and projects get done faster and cheaper.
6. Makes resource contention a PM "fact of life". Resolves resource contentions explicitly. Bottleneck resource is identified by CCPM schedule.  All users of the critical resource are identified up-front and conflicts resolved.  Project Managers watch only the critical resource; constantly focusing on what's important and preventing problems from occurring.  Constraints are managed.
7. Makes multi-tasking a PM "fact of life". Minimizes multi-tasking by setting priorities. The terrible cost of multi-tasking is exposed.  All personnel are trained on "bad multi-tasking".  People hunt down & eliminate their own multi-tasking, multi-tasking forced on them by others, and multi-tasking done by others.  This alone can cut project schedules elapsed time by up to 40%.
8. Reacts to uncertainty by changing priorities, expediting, and creating a new schedule. Manages uncertainty by monitoring impact of events on buffer consumption. Project schedules and their priorities stay consistent.  People don't get confused, nor lost as readily.  The impact of one project on all other projects is minimized.  Entire organization stabilizes into busy and productive status quo activities, rather than chaos.  People feel benefits from CCPM; they are more productive, less frustrated, involved.  Their contributions & efforts matter.  Morale climbs.
9. Makes task linkages and constraints reflect ad hoc or habitual scheduling decisions. Makes task linkages and constraints reflect only physical scheduling requirements. "Sacred cows" like "we've always done it that way" get challenged.  People innovate.  Opportunities are identified automatically.  Historical systems are re-designed & changed to take advantage of theoretical opportunities; making these opportunities reality.  Rate of learning in the organization & adaptability are maximized.  Competitors are left behind with their old, non-competitive paradigms. You become a world-leader in your industry.


Fast Projects

Traditional Project Management methods usually use task duration safety factors of 3 to 4.  Most of this safety time tends to get wasted.


  • We use the most probable task durations; typically half as long as what is traditionally used.
  • We accumulate the safety time into a few manageable Buffers that project managers and Senior management can watch very closely
  • We minimize or eliminate the multi-tasking which consumes up to 60% of the project time

The total project duration is shortened by at least 10%, to as much as 50%


Reality in Project Schedules

The following image explains how a 3 week duration task grows into a 10 week task duration estimate that get used in traditional project management schedules.

With CCPM (Critical Chain), the best possible (but fair & realistic) task estimate of 3 weeks gets used in the schedule.  People realize it's very tight, but possible, and have a healthy (not crippling) level of anxiety.

Project team members work hard & fast to achieve the goals (fastest possible project implementation).

The overall CCPM schedule keeps 3 weeks for the task, plus 3 weeks of safety time (to be shared by this task, as well as all other tasks).

CCPM (Critical Chain) quickly and easily reports who is using up the safety time, and asks the question, WHY?

Social pressure of the project team causes everybody to conserve overall safety time, rather than using more than their "fair share" of the overall safety time.

The end result is the project task gets done on-time and on-budget.

 50/50 chance task durations, and 90% chance durations for CCPM (Critical Chain)

Critical Chain Project Management (CCPM) allows your project plan to match the reality of how people work.

Classical project management assumes everyone will exactly follow the formally defined schedule.  Reality is adjusted for by the use of excessive supervision, pressure, expediters, excessive co-ordination meetings, re-baselining, pleading, scope reduction, feast & famine activity levels, overtime, etc.

People are not robots who tirelessly do everything right, exactly when they are supposed to.  Not even robots do that!  We all know that:

  • People get bored at mundane tasks.

  • They get overwhelmed by too much information given too quickly.

  • People get nervous & frustrated when everything seems to be changing, especially when it occurs rapidly or continuously

  • People have personal priorities ("pet projects" & private agendas)

  • People tend to do what they like doing, before they do what they have to do.

  • Each person does certain tasks very well, and others they shy away from.

  • Most people tend to be optimists, and assume things will go better than they really do.

CCPM doesn't demand people to be "perfect little robots" in order to work together effectively.  Instead, it assumes that people are human, with strengths and weaknesses.

CCPM supports the people by adding strength where people need help, and allowing people freedom to create and work in areas where they naturally excel.

CCPM provides the strong structure that people and organizations need, while permitting the flexibility and individualism that we all want.

CCPM is simultaneously strong and flexible.

  Simplicity in Project Management

Many of us have designed or planned projects where everything known about the project, the deliverables, and the people was put into the schedule.

Hundreds, if not thousands of related pieces of information are entered into the system.  Small changes occur, resulting in obsolete data which we don't have the desire, nor the resources to keep up-to-date.  

CCPM works on the philosophy that :


It is far better to be
approximately correct
exactly wrong


Instead of thousands of tasks and micro-management that traditional project management methods use, CCPM lets us define and effectively manage the most complex project with 300 tasks (or less).

More tasks and details may give us the illusion of control, but excessive detail removes our ability to see, decide, and act effectively & swiftly.


Control of Your Projects

Managers are responsible for producing the deliverables on-time, within budget, while using the assigned resources.

If a manager knows that a significant problem may soon arrive, they can take effective preventive actions before the project is adversely affected.

CCPM produces: 

  • "Who does What & When" reports so everybody knows what to expect

  • "Fever Charts" and "Buffer Reports" so managers can see how they have consumed or protected their precious safety time buffers, and accurately predict when the project will complete.

  • Hierarchical resource assignments so that tasks go to the least specialized resource who is competent at doing that task.


Software Applications for Project Management

Not all project management software was created the same; especially in how the implement CCPM.

See PQA's brief overview on the major project management software.

Free PM System Questionnaire

In order to build a world-wide database for an up-coming research paper being developed by PQA, we are collecting data on the current status of Project Management systems around the world.  To assist this research effort, PQA is making their Project Management System Survey Questionnaire  available to you free of charge; previously only available to PQA's clients.  Download the form, fill it in, analyze your results.  We ask that you share your results with PQA in confidence, so as to advance our research into CCPM and Project Management.

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