1. What is Schedule Performance Index (SPI)?

The Schedule Performance Index (SPI) is a project management metric that measures schedule efficiency. It compares the earned value (EV) of work performed to the planned value (PV) to determine if a project is ahead of or behind schedule.

2. How Does the Calculator Work?

The calculator uses the SPI formula:

Where:

• \( EV \) — Earned Value: The value of work actually completed
• \( PV \) — Planned Value: The value of work planned to be completed

Interpretation:

• SPI > 1.0: Project is ahead of schedule
• SPI = 1.0: Project is on schedule
• SPI < 1.0: Project is behind schedule

3. Importance of SPI Calculation

Details: SPI is a critical metric in earned value management that helps project managers track schedule performance, identify potential delays early, and make informed decisions to keep projects on track.

4. Using the Calculator

Tips: Enter both EV and PV in dollars. Both values must be positive numbers, with PV greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between SPI and CPI?
A: SPI measures schedule efficiency (time), while CPI (Cost Performance Index) measures cost efficiency (budget).

Q2: Can SPI be greater than 2.0?
A: Yes, though uncommon. SPI > 2.0 indicates the project is significantly ahead of schedule, which may warrant investigation into estimation accuracy.

Q3: How often should SPI be calculated?
A: Typically calculated at regular reporting intervals (weekly, monthly) throughout the project lifecycle.

Q4: What are limitations of SPI?
A: SPI doesn't account for critical path activities and may not reflect the true schedule status if the project plan is inaccurate.

Q5: How can I improve a low SPI?
A: Options include reallocating resources, adjusting schedules, fast-tracking activities, or revising project scope.