Decision Making Decision method
Relates optimistic, likely, and pessimistic values to derive a range, expected value, and risk picture.
Three different views of the same work are combined instead of asserting a mean without context. Uncertainty becomes a planning range and expectation. The approach is useful when buffers and risk need a clear rationale.
What range and triangular expected value follow from a plausible optimistic, most likely, and pessimistic scenario?
The steps form one complete method run.
Scope
Define work, unit, Done, and included risks unambiguously.
Scenarios
Derive O, M, and P from concrete conditions and analogies; verify O ≤ M ≤ P.
Calculate
Compute triangular expected value E=(O+M+P)/3 and preserve the range separately.
Drivers
Inspect M→P and O→M gaps for dominant uncertainty and controllable actions.
Use
Use the estimate for a named decision and schedule review after scope or evidence changes.
Add new evidence at review and version estimates with the prior state.
Bei Aufwand, Zeit oder Risiko wirkt ein einzelner Schätzwert oft zu glatt für die reale Unsicherheit. Three-Point Estimation zieht Optimismus, Wahrscheinlichkeitswert und Pessimismus zusammen und macht Spannbreiten belastbar.
Three-point estimate with O/M/P scenarios, triangular expected value (O+M+P)/3, range, drivers, and review trigger.
Fictional example
Fictional values show the actual method fields.
| Work package | O · optimistic | M · most likely | P · pessimistic | Calculation | Range | Driver | Review |
|---|---|---|---|---|---|---|---|
| Provider tokenAdd evidence and rationale. | 4 days · API fits | 7 days · normal adaptation | 16 days · migration + certification rework | (4+7+16)/3 = 9 days | 4–16 days | Migration/certification | After trial import |
All values are fictional.
Close work package, unit, Done criterion, and dependencies; define O, M, and P as scenarios rather than target values.
A single estimate for effort, time, or risk often looks too smooth for the real uncertainty behind it. It separates options, evaluation criteria, and open risks. The result is captured as a Three-Point Estimate, Risk Range, and Assumption Notes.
Three different views of the same work are combined instead of blindly asserting an average. This does not hide uncertainty but translates it into a plannable range and expectation. The method is especially useful when buffer and risk need to be justified cleanly.
Three-Point Estimation forces uncertainty into the open. The optimistic value describes a favorable but realistic path, while the pessimistic value describes an unfavorable but still plausible path. The most likely value is where experts see the highest probability. The three values can feed simple ranges, risk discussions, or weighted approaches such as PERT.
Clarify whether effort, duration, or cost is being estimated. Ask for realistic extremes rather than fantasy scenarios. Use the width of the range to discuss risk, dependencies, and missing information.
The method guide walks execution through 5 phases, timing, 5 pitfalls, and clear stop criteria.
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Set subject, data, roles, flow, and review.
To be confirmed
To be confirmed
Complete run Time: 30–60 minutes per work-package group; evidence collection extra.
Complete this worksheet on paper or in your own document during the work.
| Work package | O · optimistic | M · most likely | P · pessimistic | Calculation | Range | Driver | Review |
|---|---|---|---|---|---|---|---|
| Provider token |
The blank worksheet contains prompts only.
Reference · original teaching example
Expected artifact: Estimate frame
Define work, unit, Done, and included risks unambiguously.
Entry:
...
Expected artifact: Three values
Derive O, M, and P from concrete conditions and analogies; verify O ≤ M ≤ P.
Entry:
...
Expected artifact: Expected value
Compute triangular expected value E=(O+M+P)/3 and preserve the range separately.
Entry:
...
Expected artifact: Uncertainty view
Inspect M→P and O→M gaps for dominant uncertainty and controllable actions.
Entry:
...
Expected artifact: Planning range
Use the estimate for a named decision and schedule review after scope or evidence changes.
Entry:
...
...
Method guide: https://methodatlas.meierhoff-systems.de/en/methods/three-point-estimation/run-sheet
Fitting alternatives with decision guidance, followed by other related methods.
Instead of Three-Point Estimation, choose Planning Poker when you want to calibrate estimates relative to each other and surface shared assumptions.
Instead of Three-Point Estimation, choose Ideal Days when you want to express effort in pure working days and keep team calibration manageable.
Moves options, criteria, and risks toward a concrete result through "clarify the estimate object and unit", "collect independent estimates", and "document another round and the outcome".
Moves backlog, sprint work, and team flow toward a concrete result through "clarify the planning question", "slice work smaller", and "calibrate regularly with reality".
Bundles expert estimates across rounds until ranges, consensus, and assumptions become solid enough.
Clarifies options, criteria, and risks by framing the central question, recording the main claim, and marking weak spots.
