Definition
An assumption is a proposition treated as true for the purpose of analysis or decision-making although it has not yet been fully confirmed.
Human Explanation
An assumption allows analysis to continue when not all necessary information is available.
Why it Matters
Every decision relies on assumptions. Identifying and testing the most important ones improves the credibility of analysis and reveals where uncertainty may change the decision.
Conceptual Boundary
An assumption is not a fact, evidence or a prediction. It is a provisional basis for reasoning and should be revised when new information becomes available.
Practical Perspective
Document assumptions explicitly, identify which conclusions depend on them and prioritise validation of assumptions that are both uncertain and capable of changing the preferred action.