Once a team has a preferred explanation, supporting examples become easy to notice. A lost sale proves the price is wrong; a won sale proves the new positioning works. The same evidence can be recruited to defend different stories.
Write the hypothesis plainly
State the claim in a way that can be challenged. “Customers leave because onboarding is confusing” is more useful than “we need a better experience”. It suggests what to inspect and what alternative explanations might exist.
Record what evidence would make you change your view before collecting more examples. Otherwise the criteria can move whenever an inconvenient result appears.
Find contrasting cases
Compare customers who stayed with those who left, or projects that flowed with those that stalled. Look for meaningful differences rather than selecting only the most memorable stories.
A satisfied customer who experienced the supposedly decisive problem may reveal that another factor matters. An unhappy customer who never encountered it may reveal a second problem.
Ask neutral questions
Avoid telling the interviewee your preferred explanation. Ask them to describe the sequence, the alternatives considered and the moment their decision changed. Their account is still imperfect evidence, but it is less useful if you supply the answer first.
Update the working model
Keep what the evidence supports and narrow what it does not. Changing a hypothesis is progress when it produces a better decision. The goal of research is not to make the original strategy feel correct; it is to reduce the cost of being wrong.