It compares the work finished with the estimates made at the beginning of the project, which gives a measure of how far the project is from being finished. Inferring from the amount of work already put into the project, a project manager can get reasonable prediction as to how much resources the project will have used at completion.
EVM was used in the 1800s as industrial engineers looked for ways to measure performance in factories. The United Stated Department of Defense (DOD), in the 1960s, employed the Cost/Schedule Control System Criteria (C/SCSC) which is now referred to as the Earned Value Management System (EVMS), a recognized function of program management, which ensures that technical, cost, schedule, and aspects of a contract are truly integrated. The DOD used the C/SCSC cost system simply because their contractors ran over budget, lag behind schedule, had no ability to guesstimate an acceptable cause-effect relationship of how cost, schedule or scope impacted multiple and simultaneous projects. As a result, the government requested that contractors were no longer permitted to forecast costs by subtracting project actual costs from the original budget. ...Show more