What are the Four Big Risks?
The Four Big Risks is a framework to help product managers consider what could go wrong, before moving ahead to actually develop a feature. The four risks are: Value risk (users won't buy or want to use it), Usability risk (users won't be able to use it), Feasibility risk (it will be harder to build than thought), and Business Viability risk (it will not fit with our overall business model).
The Four Big Risks were originally conceived of by Marty Cagan at SVPG.
Assumption mapping is a method to reveal these risks, and they can be investigated further by conducting different tests and experiments, called product validation techniques.
The Four Big Risks are part of the work on solution risk validation done in the discovery part of the product management process, often in conjunction with work on an Opportunity Solution Tree.