It provides the basis for measuring and reporting schedule performance. The original baseline is maintained as the original baseline for post-project evaluations. Progress measurement techniques such as earned value help to assess the magnitude of any variations which do occur. Time control will decide if the schedule variation requires corrective action called variance analysis . Revisions are a special category of schedule updates.
Revisions are changes to the scheduled start and finish dates in the approved project schedule.
These dates are generally revised only in response to scope changes. Some extreme cases would case rebaselining to occur. Expediting causes special actions to be taken to ensure completion of an activity on time or with the least possible delay. Heuristic Scheduling rule of thumb is to multiply by 2 for end result. The critical path is the longest track through the network.