Schedule Performance Index (SPI): An Introduction

Schedule Performance Index (SPI): An Introduction

The Schedule Performance Index (SPI) is part of a greater project performance measurement method called earned value management (EVM). It is a ratio of earned value to planned (or actual) value, which reflects a project being on schedule, behind schedule or ahead of schedule. SPI measures the value of work completed by comparing the progress we planned to make to the actual progress made. To calculate the SPI, it is important to understand the key terms and how to calculate it for yourself.
Earned Value Management (EVM) is a technique used to measure the performance of a project. The schedule performance index (SPI) is a ratio of earned value to planned value, and is calculated by dividing this earned value integer by the planned value integer. The cost performance index (CPI) is the measure of the value of work in comparison to cost, and is different from the schedule performance index in that CPI measures cost efficiency while SPI measures time efficiency. To calculate SPI, the project managers must find the earned value (EV) and the planned value (PV), and then divide the two by the earned value integer.