A project that should have been 90% complete by now is only 65% complete. The total project budget is US$120,000 and the actual cost spent to date (AC) is US$80,000.
What is the scheduled performance index (SPI) and cost performance index (CPI) of this project?
EV = % complete * budget: 65% * $120,000 = $78,000,
AC = $80,000.
CPI = EV/AC = $78,000/80,000 = 0.975 or 0.98
A CPI less than 1 means the project is over budget.
PV = % complete * budget: 90% * $120,000 = $108,000,
SPI = EV/PV = $78,000/108,000 = 0.72
An SPI less than 1 means the project is behind schedule.