Assign times for each task in each path. Identify the longest path in the PERT diagram. This is the critical path because it sets time constraints on the whole project. If, say, the critical path ...

The critical path is the most important part of the diagram for managers ... the project completion time and should be watched closely, and which activities involve slack time and can be delayed ...

The critical path is the longest sequence of activities in the network diagram that must be completed in order to finish the project, and it represents the shortest possible time for completion.