Assumptions and method
Use the same team and definition of done; do not compare teams using story points. The range is an observed-rate scenario, not a confidence interval.
Test a scenario
Use the result in a decision
Use consistent workflow boundaries and observation periods.
Use the same team and definition of done; do not compare teams using story points. The range is an observed-rate scenario, not a confidence interval.
Set a baseline and change one assumption to compare outcomes.
A worked example
Follow the fixed teaching example
- Observed mean rate = (18 + 22 + 20 + 16)/4 = 19 units per iteration.
- 95/19 = 5 iterations. Round up 95/16 to 6 at the slowest observed rate and 95/22 to 5 at the fastest.
These illustrative inputs describe a project scenario, not a published benchmark. All monetary inputs use the same currency and price basis.
- Remaining units of work
- 95
- Completed units per recent iteration
- 18, 22, 20, 16
- Mean observed rate
- 19 units/iteration
- Iterations at mean rate
- 5
- Iterations at slowest observed rate
- 6
- Iterations at fastest observed rate
- 5
Interpret the output only within the assumptions above. Changing the inputs changes the result; it does not validate the inputs.
Source & credit
Standard estimating practice; the cited guide documents use rather than claiming invention.
GAO: Cost Estimating and Assessment Guide
This is independently written code and explanation of the underlying method. The linked publication, its diagrams and its trademarks remain its owner’s material; no permission to reuse them is implied.