Schedule Performance Index (SPI)
The Schedule Performance Index (SPI) is a measure of schedule efficiency, expressed as a ratio of earned value to planned value. If a project's SPI is less than 1.0, it means the project is behind schedule. Conversely, an SPI of greater than 1.0 indicates the project is ahead of schedule. The SPI focuses on the efficiency of the time utilization on the project, enabling project managers to better manage their schedules and providing valuable guidance on whether there may be a need to adjust resources, or priorities.
Guide to Schedule Performance Index (SPI)
Importance: Monitoring SPI is essential for project managers to assess schedule performance, track progress, and forecast future performance. An SPI less than 1 indicates a need for corrective action.
Working: SPI is calculated as EV divided by PV. For example, if a project has an EV of $80,000 and a PV of $100,000, the SPI would be 0.8, indicating the project is behind schedule.
Exam Tips:
1. Understand the formula and meaning of SPI.
2. Remember that SPI less than 1 means the project is behind schedule. An SPI more than 1 means the project is ahead of schedule.
3. Practice interpreting SPI values in various scenario questions.
Answering Exam Questions:
When answering SPI related questions, remember to:
1. Carefully read the question, noting all values given.
2. Apply the right formula – EV / PV.
3. Interpret the resultant value correctly, i.e., less than 1 is behind schedule and greater than 1 is ahead.
4. In situational-based questions, use the SPI value to determine if corrective action is required and suggest appropriate strategies.
CAPM - Schedule Performance Index (SPI) Example Questions
Test your knowledge of Schedule Performance Index (SPI)
Question 1
A tech company has an EV of $18,000, AC of $15,000, and PV of $22,000 in its big data project. The SPI is less than one. What if the company finishes its project today, a week earlier than planned?
Question 2
A company is completing an energy efficiency project. The EV is $10,000, PV is $8,000, and AC is $9,000. However, the energy savings are less than predicted. How might they improve the SPI?
Question 3
In the middle of an e-commerce project, the SPI dipped from 1.2 to 0.9. What should be the project manager's main attention area?