A project manager is overseeing a complex infrastructure project with multiple interdependent work packages. The project is currently in its execution phase. The team has completed Work Package A, which was planned to be finished in 10 weeks at a cost of US$200,000. It actually took 12 weeks and cost US$240,000. Work Package B, which has a planned duration of 8 weeks and a budget of US$160,000, is now starting. What is the Schedule Performance Index (SPI) and Cost Performance Index (CPI) for Work Package A?

Correct answer: D. SPI = 0.83, CPI = 0.83

SPI = EV / PV. Since Work Package A is complete, EV = BAC for Work Package A = $200,000. PV = Planned Value, which is the value of work planned to be completed. If it took 12 weeks for 10 weeks of planned work, PV is still $200,000 because all planned work for WP A is now complete. So SPI = $200,000 / $200,000 = 1. Oh, wait. This is a common trick. For SPI, 'planned' refers to the *rate* or *duration* of planned work, not just the total budget. If it took 12 weeks to do 10 weeks of work, then the actual *rate* of progress is slower. SPI should be calculated based on the earned value (what was planned to be done) divided by the planned value (what was actually planned to be done by the actual time spent). For a completed work package, EV is the planned cost (BAC) of that package. The PV for the duration it actually took would be proportionally higher if the work was completed in more time. Let's re-evaluate based on standard definitions: EV = Earned Value, AC = Actual Cost, PV = Planned Value. SPI = EV / PV. CPI = EV / AC. For Work Package A: Planned Duration (PD) = 10 weeks, Planned Cost (PV_total) = US$200,000. Actual Duration (AD) = 12 weeks, Actual Cost (AC) = US$240,000. Since Work Package A is complete, the Earned Value (EV) for Work Package A is its total planned cost: EV = US$200,000. To calculate SPI, we need the Planned Value (PV) for the duration it actually took. The planned value for 12 weeks, if the work was planned to take 10 weeks for $200,000, is not simply $200,000. It's the budgeted cost for the work that was *scheduled* to be completed by the point in time the measurement is made. If the work was *planned* to be completed in 10 weeks for $200,000, and it took 12 weeks, then the PV for the *actual* duration of 12 weeks would technically be higher if we were looking at a point in time before completion. However, once a work package is *completed*, the EV is the BAC for that package, and the PV used for SPI is typically the BAC of the work that *should have been completed* by the reporting date. If the work package was planned to be finished by week 10, then by week 12, the PV for that work package is still its total planned value, $200,000, assuming it was meant to be 100% complete by week 10. Let's use the simplest and most common interpretation for a completed work package: EV = BAC (Budget at Completion for Work Package A) = US$200,000. PV = BAC (Budget at Completion for Work Package A) = US$200,000 (because the work was planned to be completed). AC = Actual Cost = US$240,000. SPI = EV / PV = US$200,000 / US$200,000 = 1.0. This can't be right if it took longer. The correct way to interpret SPI for a completed task that took longer than planned is: EV is the value of the work *actually performed* (which is the full planned value once completed), and PV is the value of the work that *should have been performed* by the actual completion time if it had stayed on schedule. Another way to think about it is: SPI = (Budgeted Cost of Work Performed) / (Budgeted Cost of Work Scheduled). If it took 12 weeks to do 10 weeks of work, then the work was performed at 10/12ths the planned rate relative to time spent. SPI = Planned Duration / Actual Duration = 10 weeks / 12 weeks = 0.833. CPI = EV / AC = US$200,000 / US$240,000 = 0.833. Therefore, SPI = 0.83 and CPI = 0.83.