Assumption Mapping

Origin. Discovery-driven planning (McGrath and MacMillan); Bland's assumptions-mapping workshop.

Mechanism. Plots each assumption on two axes — importance to the outcome, and available evidence — and prioritizes testing in the quadrant that is high-importance and low-evidence. Attention is allocated by expected information gain rather than by comfort.

Procedure. Enumerate desirability, viability, and feasibility assumptions separately. Place each on the grid. Test the top-left quadrant first, cheapest test first.

Applies to. Before committing resources; the standard corrective to plans that are internally coherent and externally unfounded.

Limitations. Assumptions in the low-importance/low-evidence quadrant are the ones that kill projects, because the importance estimate is itself an assumption.