One-sentence brief
Confusing these categories can turn a useful thought experiment into false certainty or make a vivid counterfactual look like an official warning.
SIMULATION LITERACY
A practical distinction among exploratory scenarios, probabilistic forecasts, observations, and policy decisions.
ORIENTATION
Confusing these categories can turn a useful thought experiment into false certainty or make a vivid counterfactual look like an official warning.
WORKING BRIEF
A scenario is a structured counterfactual. It explores what may follow if stated conditions, relationships, and interventions are assumed. It can expose dependencies and failure modes without claiming that the branch will occur.
A forecast estimates what is expected within a defined horizon. It should specify a target, base rate, probability or interval, model version, issue time, and evaluation rule.
An observation is a measurement or source report. It can be incomplete, delayed, biased, or erroneous, but it should not be rewritten merely because a model expected something else.
A decision is an accountable choice made under evidence, law, values, resources, and risk. A model may inform the decision but should not conceal who chose, which alternatives were considered, or which harms were accepted.
Before publication, ask whether a reader could identify what was measured, what was assumed, what was simulated, what was forecast, and what was decided. If those states blur, the presentation needs revision.
A scenario may remain historically useful after its assumptions change, while a forecast should be scored and a factual record should be corrected. Supersession should preserve the earlier state without presenting it as current.
COMPLETE DOSSIER
Terms are defined for this site’s evidence method, not as universal legal or clinical definitions.
RESEARCH EDITION
This page follows the public method for provenance, confidence, source independence, alternative accounts, limitations, review state, and visible correction.
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