Editing Earned value management (section)

== Making earned value schedule metrics concordant with the CPM schedule ==
{{See also|Earned schedule}}
The actual critical path is ultimately the determining factor of every project's duration. Because earned value schedule metrics take no account of critical path data, big budget activities that are not on the critical path have the potential to dwarf the impact of performing small budget critical path activities. This can lead to [[Gaming the system|gaming]] the SV and [[Schedule Performance Index]] (SPI) metrics by ignoring critical path activities in favor of big-budget activities that may have more float. This can sometimes even lead to performing activities out-of-sequence just to improve the schedule tracking metrics, which can cause major problems with quality.

A simple two-step process has been suggested to fix this:
# Create a second earned-value baseline strictly for schedule, with the weighted activities and milestones on the as-late-as-possible dates of the backward pass of the critical path algorithm, where there is no float.
# Allow earned-value credit for schedule metrics to be taken no earlier than the reporting period during which the activity is scheduled unless it is on the project's current critical path.

In this way, the distorting aspect of float would be eliminated. There would be no benefit to performing a non-critical activity with many floats until it is due in proper sequence. Also, an activity would not generate a negative schedule variance until it had used up its float. Under this method, one way of gaming the schedule metrics would be eliminated. The only way of generating a positive schedule variance (or SPI over 1.0) would be by completing work on the current critical path ahead of schedule, which is in fact the only way for a project to get ahead of schedule.<ref>{{cite book
 | last = Devaux
 | first = Stephen A.
 | title = Managing Projects as Investments: Earned Value to Business Value
 | publisher = CRC Press
 | year = 2014
 | pages = 160–171
 | isbn = 978-1-4822-1270-9 }}
</ref>