Critical Chain Method is a set of practices that emphasizes the resources needed in order to be complete a project. This method was developed by Eliyahu Goldratt in his novel, Critical Chain. The Critical Chain Method is based on the Theory of Constraints, which was created to help organization achieve goals. The Theory of Constraints uses reason to help improve a company's processes.
Critical Chain takes the place of traditional methods in the way it schedules for uncertainties.
The traditional project management methods try to achieve project management goals by adding a safety net of time and trying to start work as early as possible even when it's not on the schedule, yet. Traditional methods do not allow for work to be completed early since the next person in line will not take it on before the due date.
For more information on project management methods, read The Top 7 Project Management Techniques Every Project Manager Needs to Know by Joe Taylor, Jr.
Critical Chain is Different!
This is the main reason why most projects are late. Tasks that are finished early cannot be passed onto the next phase. If the following task suffers a pitfall, it can cause the whole project to get off track. Just focusing on a due date can be dangerous. At any time during the process, Murphy's Law may come into play, destroying whatever progress has been made.
Critical Chain does the complete opposite. First of all, a project is scheduled backwards from the time of completion. This ensures that the proper task is being done and only when it needs to be done. A project is given an estimate length of time until completion. Critical chain identifies the longest sequence of a project and takes into consideration the available resources. Duration estimates (or how long a task will take) in Critical Chain are cut by 50 percent from individual tasks. This allows the extra time to be added to the project as a whole.
For more information on Critical Chain, read What is Project Management Critical Chain and How is it Different than Critical Path?
What is a Buffer?
Next, buffers will be strategically placed within the project plan to safeguard the project itself and the most important tasks. The buffer is a certain amount of time placed within a project plan to preserve the success of it. The buffer burn rate tells a project manager how much longer a project is taking over the initial estimated length of time. If a task burns 50 percent of the buffer and only a fraction of the work is done, you know that there is a problem that needs to be remedied. A high burn rate could jeopardize the entire project.
The buffer can also help a project manager control costs. A budget buffer can make your budget both tangible and manageable.
For more information on buffers, read Project Constraints: Time by Joe Taylor, Jr.
Perhaps the most important piece of this system is allowing projects to be completed early and passed onto the next person in line. Multitasking, while it allows multiple projects to be worked on at one time, is does not allow a project to be completed ahead of schedule since there's so much going back and forth between projects. Nothing actually gets done before or even on time.
In Critical Chain, only one project part or task can be tackled at a time. This allows the most "critical" aspects of the entire project to be finished, and the ensuing part of the "chain" to begin. The end of a Critical Chain project is the start of the project buffer.
What Makes Project Management Special?
But, why should a project manager be interested in the Critical Chain Method? Critical Chain projects typically come in at or under budget; they use fewer resources than traditional methods of project management. Companies can see at least a 10 percent and often as much as a 50 percent improvement overall through better scheduling, less multitasking and more elevated communication.
Critical chain is important for completing projects on time and within budget. It should be seriously considered by any project manager looking to advance his organization.
For additional information on Critical Chain, read Ronda Levine's article What is Critical Chain?