HKSM
S-Curve Analysis
A chart that plots the running total of cost, effort, or completed work over time so you can see trends, pace, and deviations from plan.
Key Points
- Visualizes cumulative values (planned vs. actual) across time to reveal trends and variances.
- Commonly paired with earned value data (PV, EV, AC) to assess performance and forecast outcomes.
- Typical pattern starts slow, accelerates mid-project, then tapers as work completes (S-shape).
- Requires consistent time periods and a stable baseline for meaningful comparison.
Example
On a 10-sprint software project, the team builds an S-curve comparing planned cumulative story points to actual completed points. By sprint 5, the actual curve sits below plan, signaling slower throughput. The team adds test automation and trims low-priority scope; by sprint 9, the actual curve converges with the plan.
PMP Example Question
Which tool best shows cumulative cost, labor, or progress over time so that planned and actual performance can be compared?
- S-Curve Analysis
- Resource Histogram
- Control Chart
- Pareto Diagram
Correct Answer: A — S-Curve Analysis
Explanation: S-curve analysis charts cumulative values over time, making it ideal for comparing planned and actual performance and spotting trends.
