Editing Earned value management (section)

== Earned value (EV) ==
<math display="inline">
\begin{align}
\mathrm{EV} & = \sum_\mathrm{Start}^\mathrm{Current} \mathrm{PV(Completed)} \quad \mathrm{or} \quad \mathrm{EV} = \mathrm{budget\, at\, Completion\,(BAC)} \times \mathrm{Actual\%\, Complete}
\end{align}
</math>

EV is calculated by multiplying %complete of each task (completed or in progress) by its planned value

'''Figure 2''' shows the EV curve (in green) along with the PV curve from Figure 1. The chart indicates that technical performance (i.e. progress) started more rapidly than planned, but slowed significantly and fell behind schedule at week 7 and 8. This chart illustrates the schedule performance aspect of EVM. It is complementary to [[critical path method|critical path]] or [[critical chain]] schedule management.

'''Figure 3''' shows the same EV curve (green) with the actual cost data from Figure 1 (in red). It can be seen that the project was actually under budget, relative to the amount of work accomplished, since the start of the project. This is a much better conclusion than might be derived from Figure 1.

'''Figure 4''' shows all three curves together – which is a typical EVM line chart. The best way to read these three-line charts is to identify the EV curve first, then compare it to PV (for schedule performance) and AC (for cost performance). It can be seen from this illustration that a true understanding of cost performance and schedule performance ''relies first on measuring technical performance objectively.'' This is the ''foundational principle'' of EVM.