| Term | Meaning |
|---|---|
| Option | One of the choices. The current approach is the zero baseline |
| Estimate | A number you enter. A result is a number the model calculates |
| Likely range | Low and high values with about a 1 in 10 chance outside each end (P10 to P90) |
| P10 / P50 / P90 | The values with a 10%, 50% and 90% chance of the true value being below them |
| Influence diagram | A cause-and-effect map of the decision |
| Distribution | The shape of your uncertainty: which values are more or less likely |
| Monte Carlo simulation | Playing out many random but plausible futures to see the spread of outcomes |
| Simulated future | One draw of the whole model |
| Run | One saved simulation |
| Stale run | A run made before the latest model change |
| Net value (NPV) | Benefits minus costs, in today’s money. Cash effect is reported separately |
| Discount rate | How much less money is worth when it arrives later |
| Win rule | What an option must achieve to be called a winner |
| Risk appetite | How much shortfall you accept, and how often |
| Certainty equivalent | The guaranteed amount that feels as good as taking a gamble |
| Tornado | A ranking of estimates by how much they swing the result |
| Break-even | How wrong an estimate must be before another option wins |
| EVPI | Value of perfect information: the ceiling on what learning more is worth |
| Constraint | A rule an option must or should satisfy |
| Proposal | A change suggested by research or Dave, which waits for the owner to accept it |
Reference
Glossary
The terms used across the docs.