Schedule Performance Index
Ratio
Schedule Performance Index (SPI) gauges the efficiency of time utilization in the project. An SPI less than 1 indicates a delay, while an SPI greater than 1 indicates tasks are being completed faster than planned.
Formula
SPI = Earned Value (EV) / Planned Value (PV)
Example
If the earned value is $60,000 and the planned value is $50,000, the SPI is 1.2.