Earned value, lead and cycle time, velocity and variation. How to tell whether delivery is on track, and which of the numbers quoted at you mean anything.
Articles
Two ratios off one earned value figure. SPI divides it by the plan and reads schedule. CPI divides it by the bill and reads cost. Below 1 is bad news in both, for different reasons.
Three figures read at one date. Planned value is what the baseline said would be finished by now, earned value is what did finish, actual cost is what finishing it cost.
Terms
The costs genuinely incurred for the work counted as earned value, up to a given date. Actual cost only means something when it covers the same scope earned value covers.
Earned value divided by actual cost. Below 1 means the completed work cost more than its budget, above 1 means it cost less.
The budgeted cost of the work actually completed at a given date. Earned value prices finished work at baseline rates, never at what the work really cost.
The budgeted cost of the work the baseline scheduled to be complete by a given date. Planned value = budget at completion × planned percent complete.
Earned value divided by planned value. Below 1 means less work is complete than the baseline scheduled by that date, above 1 means more.