Estimated (costs) at completion (EAC): BAC divided by CPI. The answer is a forecast value in either dollars or hours that indicates the projected final project costs or time. There are various formulas for EAC, McCauley says, but this is one of the easiest to use. In our example, that's 200/0.83 = 240.96. This indicates that at the rate we're going, the final cost will be $240.96 rather than our planned $200.

Schedule variance (SV): Subtract PV from EV. In our example, our earned value is $50 because we've done the first of our four phases: We bought the system. The PV for that first phase was actually $50. So 50 - 50 = 0. That's a perfect score, so we're on schedule.

Cost variance (CV): Subtract AC from EV. In our example, that's 50 - 60 = -10, indicating that we've overspent by $10. If we were on target, CV would be zero.

Pratt is a Computerworld contributing writer in Waltham, Mass. Contact her at marykpratt@verizon.net.