Diagnostic module
What Problem-Solution Fit means
If the problem is not painful, the product should not advance.
This stage answers two questions
- Does a defined user group experience a real, recurring pain?
- Does the proposed solution create enough pull to keep testing?
Diagnostic module
Why it matters
Most product failure starts here, not later.
What teams get wrong
- Interest is mistaken for evidence.
- Positive feedback is mistaken for demand.
- A build starts before the problem is verified.
Diagnostic module
Common mistakes
Problem–Solution Fit fails when the test protects the idea instead of challenging it.
Failure patterns
- Leading questions that push users toward agreement.
- Friend, investor, or advisor reactions treated as user evidence.
- Enthusiasm treated as willingness to pay.
- Market-size data treated as proof of pain.
Diagnostic module
Evidence and verdict rules
Strict inputs only. Missing proof does not receive interpretation credit.
What counts as evidence
- Real users with verifiable source material.
- Observed behaviour tied to the stated pain.
- Preference, pull, or payment from actual testing.
What scores zero
- Paraphrased summaries without source material.
- Team belief or founder conviction.
- Projected future behaviour used as current proof.
Diagnostic module
How to test it
Run the stage, identify the missing proof, then generate only that evidence.
Use the loop
- Run Problem–Solution Fit.
- Find what still scores zero.
- Generate the missing proof.
- Re-run before moving to Product–Market Fit.