The Schedule Performance Index is a measure of project efficiency given by Project Management to gauge the progress and efficiency. A Schedule Performance Index score of 1 or greater is an optimum goal since it shows the Project Management that the project is on track and has favorable conditions of meeting the required goals. However, a of Schedule Performance Index less than 1 is to be avoided since that shows the project is not meeting goals and is showing unfavorable conditions that could lead to project failure if the current course of action is allowed to continue. If the is Schedule Performance Index showing a trend that is at or approaching 1, the Project Management will re-evaluate the current conditions of the project and begin an analysis of the current project trends and begin corrective actions. If the Schedule Performance Index trend is rising, the Project Management w ill analyze the goals and the current favorable conditions to possibly re assess the project’s short term goals. The Schedule Performance Index is a ratio of Earned Value (EV) to the Planned Value (PV). Earned Value is the value of the project at its current timeframe. Planned Value is the overall projected value of the project at the same time as the Earned Value. To determine the project’s Schedule Performance Index the Project Management divides the EV by the PV. This can also be shown as a simple formula; SPI=EV/Pv.
This term is defined in the 3rd and the 4th edition of the PMBOK.