Theory of Constraints, the Five Step Critical Chain Process has tremendous advantages over the traditional Project Management PERT/Critical Path approach. Buffer Management is applied, which provides a focused method for identifying and working only on the issues that are causing or may cause time to be lost on the critical chain.

The longest chain, in terms of time, of dependent steps may not be the critical path.  Therefore dependencies between steps can be a result of a path and/or a common resource.  Since the dependencies between steps is not necessarily a result of a path, then the constraint of a project is not necessarily the critical path.  Therefore the constraint of a project is the longest chain, in terms of time, of dependent steps (where the dependencies are a result of paths and/or common  resources). Goldratt states this as the definition for critical chain.