If we have done all the work planned for week 1 and 25% of the work planned for week 2 … we have only completed what should have cost $20,000 + $22,000/4 = $25,500 (如果我们完成了第一周的全部工作,和第二周工作的25%,通过计算完成这些工作,实际上我们仅仅应该花费25,500)
So we are actually overspent by $4,500! (所以说实际上我们多花费了25,500元)

下面是几个参数的介绍
Earned value = sum of the (up to date) budget for each of the completed items [$25,500]
Cost performance indicator = Earned value/actual spend [0.85]

Schedule performance indicator = earned value/planned spend [0.61],A SPI of 1 means the project is on schedule. Greater than 1, then the project is ahead of schedule and less than 1 means the project is behind schedule.

这个就是一个非常简单的EV management的例子.
Earned value management is a project performance measurement technique that integrates scope, time and cost data. Given a cost performance baseline, PM’s can determine how well the project is meeting scope, time and cost goals by entering actual information and then comparing it to the baseline.
通过EV management,可以用来估算project是否超时,预算是否透支,或者来或者大致的工程结束时间.