The Expert Says
Question: What role does the Critical Path play in EV Analysis?
The Expert Says: In our example the positive schedule variance indicates the project is ahead of schedule. However, the critical path for this project is A – C – E and requires additional evaluation. Delays on the critical path will impact the end date and deserve special attention. Here task A is on the CP and is significantly (10%) behind schedule. Be careful when analyzing project totals for SV and SPI as the Critical Path is not directly taken into consideration!

The Expert Says
Question: Should the PM use slack at will?
The Expert Says: Slack is a great tool for the Project Manager to help manage the project schedule and complete the project on time. Slack is really "flexibility" in the schedule along the non-critical paths which can be utilized when required to compensate for unforeseen circumstances. Slack should be used with discretion because using slack will decrease the "flexibility" and move non-critical paths closer to becoming critical.

The Expert Says
Question: If we know how far we can crash all the tasks, why don't we just crash them at them all the way and avoid working the iterative process?
The Expert Says: Be careful not to shorten the tasks on the critical path too much, otherwise we may not be spending our money efficiently. In the diagram below, the "all crashed" line shows us by adding resources to all tasks, we can finish in 22 days instead of 29 days. By taking the iterative approach we have saved money by not crashing all tasks. By adding resources to tasks A and D, we can finish between 22 and 23 days. Adding resources to only task A would allow the project to be completed in 23 to 24 days. If we shorten only task G, 25 days; only task C, 26 to 27 days, and only task E, 28 days. Keep in mind the cost is increased when we crash each task to