What implication does an SPI value of less than 1.0 have?

An SPI (Schedule Performance Index) value of less than 1.0 indicates that the project is not progressing as anticipated concerning its planned schedule. The SPI is calculated by dividing the Earned Value (EV) by the Planned Value (PV). When the SPI is below 1.0, it means that the amount of work actually completed (EV) is less than what was planned by this point in the project (PV).

This condition signifies that there are delays or issues impacting the project's timeline, causing it to fall behind the established schedule. Monitoring the SPI allows project managers to identify areas that require attention to mitigate delays and realign project efforts to meet deadlines. The lower the SPI, further behind schedule the project is, prompting necessary adjustments in project management strategies to get back on track.