Using an activity plan as its basis, the PERT Chart is used to define the critical path of a project. Used after an activity plan has been created to show the tasks needed to complete the activity and their relative timing. Also used during the implementation of the project to monitor the status. The project team should keep a constant eye on the critical path. This is the shortest amount of time that the implementation can be completed in. If any task on the critical path slips, then the timing of the entire implementation will slip.