How to calculate SV and SPI?

SV (Schedule Variance) and SPI (Schedule Performance Index) are key indicators in project management methodology based on Earned Value Management (EVM).

• Schedule Variance (SV) shows the deviation from the schedule and is calculated as the difference between the earned value (EV) and the planned value (PV):

  SV = EV - PV
  

  If SV > 0 — the project is ahead of schedule, if SV < 0 — it is behind.

• Schedule Performance Index (SPI) is the schedule performance index, showing the efficiency of time utilization:

  SPI = EV / PV
  

  If SPI > 1 — the project is progressing faster than planned, if SPI < 1 — slower.

Example:

If currently planned to perform work worth 100 thousand rubles (PV), and actually performed work worth 90 thousand rubles (EV), then:

SV = 90,000 - 100,000 = -10,000 (delay)
SPI = 90,000 / 100,000 = 0.9 (efficiency below 1)