Critical Chain Buffer Sizing: A Comparative Study

Successfully implementing a project plan hinges on the project manager's ability to develop a schedule that accommodates both the project's activities and its setbacks. This paper examines how project management can apply critical chain project management (CCPM) to plan uncertain project activities. In doing so, it describes--mostly in relation to the Theory of Constraints--CCPM's six principles; it identifies the main challenges involved in using CCPM. It then outlines several equations that can help project managers calculate the underlying variability which could affect a project schedule's critical chain activities; it explains the SMC method for developing estimated project schedule buffers, noting the logic that informs this approach and the process of using Monte Carlo Simulation for gauging project buffer sizing. It recommends an experimental design approach for assessing the impact of sizing methods; it lists the three methods which the author considered for sizing the study's buffers. It also discusses the impact of using buffers to identify the duration of scheduled project activities; it compares the performance of different buffers and discusses this study's findings.