What distinguishes CPM from PERT in project scheduling?

The distinction between Critical Path Method (CPM) and Program Evaluation and Review Technique (PERT) fundamentally lies in their treatment of project time estimates. The correct answer highlights that CPM uses deterministic durations for tasks, meaning that the time required to complete each task is fixed and known. This allows for a clear and straightforward schedule based on these set durations, which is essential for determining the critical path of the project—those tasks that must be completed on time to ensure the project finishes as scheduled.

On the other hand, PERT employs probabilistic durations, which reflect the uncertainty and variability in task completion times. In PERT, tasks are estimated in terms of three different time frames: optimistic, pessimistic, and most likely. This approach allows for a more flexible scheduling framework that accounts for potential delays and uncertainties inherent in project execution. This is particularly useful in research and development projects where time estimates may not be as predictable.

Understanding this core difference is essential for professionals involved in project management, as it influences decision-making, risk management, and overall project planning strategies. The other options, while they may include some aspects related to CPM or PERT, do not accurately capture the fundamental distinction between these two methodologies.