Equations
Project managers can use multiple equations to track the progress of their projects against their expectations. Most of the calculations compare measurements of actual costs or time used to what was planned. A few calculations figure what performance would be required to get the project back to the planned values.
Related: earned value management
The following table shows some of the equations...
| Initials | Spelled Out | Formula |
|---|---|---|
| AC | actual cost | AC = the actual cost of all the work completed by a specific time
Also known as ACWP (Actual Cost for Work Performed) |
| BAC | budget at completion | BAC = the sum of all the planned work to be performed to complete the project; the project cost baseline |
| CPI | cost performance index | CPI = EV / AC |
| CV | cost variance | CV = EV - AC |
| EAC | estimate at completion | four different formulas depending on the situation, see estimate at completion |
| ETC | estimate to complete | ETC = EAC - AC |
| EV | earned value | EV = the sum of the planned value of the work that has been completed by a particular time
Also known as BCWP (Budgeted Cost for Work Performed) |
| PV | planned value | PV = the sum of the value assigned to the work planned by a particular time |
| SPI | schedule performance index | SPI = EV / PV (where the timeframe for the EV and PV are the same) |
| TCPI | to complete performance index | TCPI = (BAC-EV) / (BAC-AC) or |
See table 7.1 in section 7.4.2.4 of the PMBOK for an "Earned Value Calculations Summary Table".