What does a schedule performance index (SPI) of 0.76 signify?

A schedule performance index (SPI) is a key performance indicator used in project management to assess the efficiency of time utilization on a project. It is calculated by dividing the earned value (EV) by the planned value (PV). An SPI value of 0.76 indicates that the project is performing at 76% of the rate that was originally planned.

This value suggests that the project is behind schedule, as a SPI of 1.0 indicates that the project is on schedule—meaning the earned value matches the planned value. Therefore, a SPI of less than 1.0 reflects an unfavorable timeline where actual progress is less than what was initially planned.

In the context of the answer provided, the interpretation that you are progressing at 76% of the original plan accurately captures the meaning of the SPI value. This understanding is crucial for project managers to assess current performance and make necessary adjustments to bring the project back on track.