HKSM

A time-based extension of Earned Value Management that assesses schedule performance in units of time rather than cost.

Key Points

• ES translates the earned value (EV) into the point in time on the planned value curve where that EV would have been planned.
• Core indicators: SV(t) = ES - AT (schedule variance in time) and SPI(t) = ES / AT (schedule performance index in time), where AT is the actual time elapsed to the status date.
• Unlike traditional SPI and SV, ES-based metrics continue to show meaningful schedule performance near project completion.
• Helps forecast finish dates, assess schedule buffers, and integrate time-focused insights with standard EVM cost metrics.

Example

A project is at week 20 (AT = 20). The earned value achieved to date equals the planned value that was scheduled for week 18. Therefore, ES = 18 weeks. SV(t) = 18 - 20 = -2 weeks (behind schedule), and SPI(t) = 18 / 20 = 0.90.

PMP Example Question

At the status date, AT = 24 weeks and ES = 21 weeks. What is the best interpretation of these results?

1. The project is 3 weeks under budget.
2. The project is 3 weeks ahead of schedule.
3. The project is 3 weeks behind schedule based on time-focused EVM.
4. The project is performing as planned because SPI is 1.0.

Correct Answer: C — Earned Schedule indicates the work accomplished corresponds to week 21 while 24 weeks have elapsed.

Explanation: SV(t) = ES - AT = 21 - 24 = -3 weeks, showing the project is 3 weeks behind schedule using the Earned Schedule method.