Critical Path

The critical path through a project schedule is the sequence of tasks which have zero float. Thus, if any task on the critical path finishes late, then the whole project will also finish late. There is always at least one critical path.

Float, or slack time, is the amount of time that a task can be delayed without affecting the completion time of the overall project.

The critical path is calculated with is the Critical Path Method (or CPM). Once the start date for the overall project is known, this will give the earliest and latest start dates for each task.

See also:

Toolbook chapter: Activity Network