Question

When activity times are known with certainty, the critical path is defined as the set of activities on a path from the project’s start event to its finish event that, if delayed, will delay the completion date of the project. Why must this definition be modified in situations where the activity times are not known with certainty? Are there dangers associated with not modifying the definition? (not more than 150 words).

Answer 1

When the time of an activity is not known with certainty, the actual duration of each path in the project is hard to evaluate, the critical path cannot be determined in this case. The problem is when there is uncertainty in the timing of each task, the critical path determined can turn out to not be the critical path due to wrong estimates of the time. It is also common for different activities to be a part of the critical path when the certainty of the time of the tasks is unknown,

For example, a project that has 5 activities which are A, B, C, D, and E with the critical path as A-B-D. The time of the activities is uncertain during the completion of each task, and the time for any activity can tend to be longer than projected here. Therefore, A-B-D can also turn out to not be the critical path if the activity C takes a longer time to complete leading to a path with the highest duration.