schedule performance index
A measure of schedule efficiency of a project.
The schedule performance index (SPI) is determined by measuring the ratio of earned value (EV) to actual costs (AC):
SPI = EV / PV
If the result is less than 1.0, the project is behind schedule.
If the result is greater than 1.0, the project is ahead of schedule
example:
| EV | PV | AC | CPI | SPI |
|---|---|---|---|---|
| 270 | 335 | 250 | 1.08 | 0.81 |