Why is it important to use Earned Value Management EVM in the overall management of projects?

Compare this to the use of baseline and current schedules only.

Please provide source.

You have been asked to calculate the Cost Performance Index for a project using earned value management techniques. It is currently day 20 of the project and the following summarizes the current status of the project:

Activity	Expected Cost	Activity Duration	Expected Start Date	Expected Completion Date	Expected % Complete	Actual % Complete	Actual Cost to Date
Start Up	$ 100,000	10 Days	0	10	100%	100%	$ 105,000
Construction	325,000	14 Days	8	22	12/14=85.714	90	280,000
Finishing	50,000	12 Days	18	30	2/12=16.667	25	2,500