CCM is a schedule method that lets a team put buffers on the project to account for resource discrepancies and project unknowns. This method adds duration buffers that are non-work schedule activities to deal with managing those unknowns. One buffer goes at the end of your project path and is called the “project buffer,” which helps to save your finish date form slippage along the way.
The next additional buffers are placed at each area where a chain of dependent activities, (these are not on the critical path, meaning they are things that can be changed and are not set in stone) are to protect the critical path. The CCM is focused on managing buffer durations against the remaining chains of activities.
In a nutshell, this method is looking to protect those crucial areas of the project that cannot be changed by adding, or subtracting time to the areas that have some give.
Danielle VanZorn PMP, SPHR