Match the test to the assumption. Use interviews for problem understanding, prototypes for usability, and real commitments for demand.
Work through it
Name the assumption
Write the belief that would make the business fail if it were false.
Choose behavior
Decide what a genuinely interested customer would do, not merely say.
Create the minimum test
Use a mockup, manual service, signup, deposit, or sales conversation.
Set the threshold
Define success before results arrive so you cannot move the goalposts.
Common mistakes
- Testing several assumptions at once
- Counting traffic as demand
- Changing the success threshold afterward