What is Assumptions Mapping?
Assumption Mapping is a method product managers can use to evaluate the risks with a product or feature before building it, to guide experiments to conduct and adaptation of the solution. The first step is to uncover risks of different type (value, usability, feasibility, viability risks). The second step is map each risk onto two scales, impact (if risk materializes) and uncertainty (about risk). The risks with high impact-high certainty need to be addressed. The risks with high impact- high uncertainty needs to be further evaluated with different product validation techniques.
Jeff Gothelf and Josh Seiden describe how to work with Assumptions Mapping in their book Lean UX.