Earned Value Management

Introduction to EVM

Essential features of any EVM implementation include (1) a project plan that identifies work to be accomplished, (2) a valuation of planned work, called planned value (PV), and (3) pre-defined “earning rules� (also called metrics) to quantify the accomplishment of work, called Earned Value (EV). EVM implementations for large or complex projects include many more features, such as indicators and forecasts of cost performance (over/under budget) and schedule performance (behind/ahead of schedule). The most basic requirement of an EVM system, however, is that it quantifies progress using PV and EV.

Project Tracking without EVM

It is illuminating to see an example of project tracking that does not include earned value performance management. Consider a project that has been planned in detail, including a time-phased spend plan for all elements of work. Figure 1 shows the cumulative budget for this project as a function of time (the blue line, labeled PV). It also shows the cumulative actual cost of the project (red line) through week 8. To those unfamiliar with EVM, it might appear that this project was over budget through week 4 and the under budget from week 6 through week 8. However, what is missing from this chart is any understanding of how much work has been accomplished during the project. If the project was actually completed at week 8, then the project would actually be well under budget and well ahead of schedule. If, on the other hand, the project is only 10% complete at week 8, the project is significantly over budget and behind schedule. A method is needed of measuring technical performance objectively and quantitatively, and that is what EVM accomplishes.

Project Tracking with EVM

Consider the same project, except this time the project plan includes pre-defined methods of quantifying the accomplishment of work. At the end of each week, the project manager identifies every detailed element of work that has been completed, and sums the PV for each of these completed elements. This accumulation is called "earned value" (EV), and it can be computed monthly, weekly, or as progress is made.

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 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.

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