The Schedule Performance Index (SPI) is a measure used in project management to indicate how efficiently the project team is using its time. It's calculated by dividing the earned value (EV) by the planned value (PV). In this case, the team planned to complete 40 story points (PV), but only completed 30 story points (EV). Therefore, the SPI would be calculated as follows: SPI = EV / PV = 30 / 40. References: = Project Management Institute's Guide to the Project Management Body of Knowledge (PMBOKGuide), 6th Edition1; Indeed's guide on Schedule Performance Index (SPI)2.