Earned Value Management is the accurate measurement of physical performance against detailed plan to allow for the accurate prediction of the final costs and schedule results for a given project. (1)

(1) Earned Value Project Management, Quentin W. Fleming and Joel M. Koppelman in Earned Value Project Management, Second Edition

If done right, the earned value management concept will provide the project manager with warning signs for cost deviations from plan as early as 15 to 20 percent into the project. This is of particular importance for geographically distributed project teams, where the project manager often doesn’t have the luxury to witness work results of all team members first hand.