Critical Chain Project Management (CCPM) is an approach to planning and managing projects that emphasizes the needs of the resources that are required to complete project tasks. Critical Chain project scheduling is different from Critical Path and PERT methods, because all work in a Critical Chain project is scheduled as late as possible in the schedule. Buffers of time are consolidated from safety margins that are removed from individual tasks and made available to an entire chain of tasks to use as necessary. These buffers protect the due dates from task overruns that occur unpredictably during project implementation. A buffer automatically absorbs the effects of late-finishing tasks, so the key to successful Critical Chain project management is correctly sizing and then managing these buffers.
Critical Chain methodology recognizes that people, not computer programs, execute projects. When a project management discipline is applied to people, human nature takes over and often results in the opposite of what the project schedule intended. Work expands to fit the allotted time, distractions appear, and unexpected conditions delay the ability to start a task on time. The knowledge that a person has ample time to complete a task generally results in the person waiting well past the safe starting time to actually work on the task.
Critical Chain project management requires a different approach to managing projects and evaluating worker performance. Critical Chain projects are managed according to a relay race analogy, as opposed to the traditional schedules employed in the Critical Path method. After work on a task chain is started, the management focus is simply to make sure the work is done as fast as possible. Like a relay race, the following runner must be prepared to take off as soon as the preceding runner hands off the baton, and not attempt to finish the race according to a published schedule. This solves the problem in traditional Critical Path projects where any time gained in one part of the schedule is lost due to waiting for the scheduled time to arrive before starting the next task. Project performance is determined simply by monitoring the utilization of the buffers. Resource contentions are resolved by analyzing the impact of allocation alternatives on buffer utilization. The complete theory, description, and practice of Critical Chain project management can be found in Dr. Eliyahu Goldratt’s book, Critical Chain.
Implementing the Theory of Constraints (TOC) for project scheduling means changing the way we think about the way schedules work. Sciforma supports the full TOC model of project management according to the principles described by Dr. Eliyahu Goldratt in his book, Critical Chain. Scheduling using Critical Chain methodology requires rethinking the way projects are both scheduled and managed in ways that at first may seem counter-intuitive:
Time estimates must not be padded—they should reflect a 50% probability of achievement.
Tasks must be scheduled to start as late as possible and scheduled backward from the target finish date.
The padding removed from each task must be consolidated into shared safety buffers.
In this theme, you will learn how to manage your project using the Critical Chain Project Management approach.
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