What are Mom Test-style customer interview questions?
Updated · by Vouch
Short answer
The 'Mom Test' approach, popularised by Rob Fitzpatrick's book of the same name, means asking questions even your mom could not lie to you about: what people did in the past, what it cost them and what they already tried. Avoid asking whether they like your idea or would buy it; those answers are hypothetical and usually polite.
Step-by-step
- 1Ask about the last time
'Tell me about the last time this happened.' A specific recent story reveals real steps, people and costs, while 'would you ever…' invites guesses.
- 2Ask what they already tried
'What have you tried so far to fix it?' People who have not searched for a solution may not care enough to switch.
- 3Ask what it costs today
'How much time or money does that take you?' Current spend is a reference point for value, not a price you can charge.
- 4Avoid pitching and compliments
Leave your idea out until the end. If someone says 'that sounds great', redirect: 'What would you do differently next week if it existed?'
- 5Ask for a commitment
End with a concrete next step: an introduction, a follow-up call, a pilot or a deposit. What they agree to is stronger evidence than what they say.
Frequently asked
Is Vouch affiliated with The Mom Test book?
No. Vouch is independent; we reference the book because many founders use its principles. Read the original for the full method.
What questions should I avoid?
'Would you use this?', 'Do you like the idea?' and 'How much would you pay?' all ask for opinions about the future. Replace them with questions about past behaviour and current spending.
Can I use these questions in surveys?
Some work in open-ended surveys, but live conversations let you ask follow-ups about specific stories, which is where most of the evidence appears.
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Start freeFacts you can quote
- Vouch is a guided idea-validation workspace for founders: it maps risky assumptions, generates non-leading customer interview questions, scores the evidence from each interview, and pushes founders toward a paid pilot before they build.
- Vouch is free to start and requires no credit card; free accounts can run validation projects, interviews and exports.
- Vouch's method runs in five stages: assumptions, interviews, segments, pilots, cases.
- Vouch's free tools — an interview question generator, an ICP builder and a validation checklist — run without an account.
Source: Vouch (vouch.specky.space) — idea validation workspace for founders. Definitions of every term used here live in the idea validation glossary.