What method would be the best way to determine the most likely as-built critical path...

Understanding As-Built Critical Path Analysis:

Determining the as-built critical path of a project involves identifying the sequence of activities that actually dictated the completion of the project. This is especially important in projects that are underway, as schedules often deviate from the original baseline due to progress updates and unplanned changes​​.

Explanation of Each Option:

A. Use the progressed portion of the critical path of all the updates previous to the current update:This is correct. To determine the most likely as-built critical path, analyzing the progressed portion of the critical path from all previous updates provides the most accurate representation of the project’s actual execution. By reviewing the progression over time, you can piece together the actual sequence of critical activities​​.

B. Use the progressed portion of the critical path of the baseline schedule:This is incorrect. The baseline schedule reflects the original plan, which may no longer be accurate due to progress deviations, delays, or changes in logic. Using the baseline alone does not account for the dynamic nature of the project​.

C. Interview the project personnel for their perceptions and opinions because the schedule is usually inadequate:This is incorrect. While project personnel may provide insights, relying solely on subjective opinions introduces biases and inconsistencies. A properly maintained and updated schedule is far more reliable for determining the critical path​.

D. Use the forward-looking critical path of the most current updates:This is incorrect. The forward-looking critical path only reflects what is expected to happen from the current point onward. It does not provide an accurate representation of the as-built critical path up to the current point​.

 Study Guide References:

The PSP Study Guide emphasizes the importance of analyzing progress updates to trace the actual sequence of critical activities. Section 2.3.2 (Tracking Schedule Progress) discusses the role of historical updates in understanding project performance​.

The guide also highlights that a proper as-built analysis requires a review of all updates to identify shifts in the critical path over time​.