What is critical path and how do you determine it?

• A. The longest path through the network diagram that determines the project duration; determine by calculating early/late start and finish and identifying zero slack paths
• B. The earliest path through the network diagram that determines project duration
• C. The path with the most resources
• D. A path with zero slack that does not affect schedule

Answer: (C)

The critical path is the longest sequence of dependent activities in your project network, and it sets the project finish date. If any activity on this path is delayed, the whole project is delayed.

To find it, map out the network with durations, then do a forward pass to get earliest start and finish times for every activity, and a backward pass to get latest start and finish times. For each activity, calculate slack (or float) as LS − ES or LF − EF. The activities with zero slack are those on the critical path. If more than one path has zero slack, there are multiple critical paths, and delays on any of them affect the overall schedule.