The Mom Test: customer conversations that tell you the truth

Who should use it, and when not to

Use it before building, while deciding whether a problem is worth solving, and in early sales conversations. It also helps teams who keep hearing "sounds great!" and then see nobody buy.

It is not a survey method for measuring how many people have a problem. Once you know the problem, size it with data. To learn why customers switched to a product, see the switch interview.

The core ideas

Everyone lies, politely. People don't want to hurt your feelings, and they're bad at predicting what they'd do. Questions about your idea invite kindness, not data.

The three rules. Talk about their life instead of your idea; ask about specifics in the past instead of hypotheticals; talk less and listen more. Together they make the conversation about facts.

Bad data. Fitzpatrick names three kinds to ignore or dig into: compliments, fluff (generic claims, future promises, hypotheticals) and ideas (feature requests). Each gets a follow-up question that finds the fact behind it.

Commitment and advancement. A meeting went well only if it ended with the customer giving something: time for the next step, an introduction, a letter of intent, a pre-payment.

Keep it casual and focused. Short conversations, often not called interviews, with a clear segment and the three most important things you want to learn.

A worked mini example

This is an illustration. A founder is building a tool that reminds clinic patients of appointments.

If the clinic owner has never tried anything about no-shows, the problem may not be painful enough. If they pay a receptionist to call every patient, it probably is.

How to run a conversation

1. Pick a narrow segment and the three things you most need to learn.
2. Open with their life: how they handle the area today.
3. Ask about the last time the problem happened, with specifics.
4. Ask what they've tried and what it cost them.
5. Dig into compliments, fluff and feature ideas to find the fact behind them.
6. Close with a request for commitment: a next meeting, an introduction or a pilot.
7. Write notes the same day, separating facts from opinions.

The interview guide skill writes a guide with past-behavior questions and no leading or hypothetical ones. To sort the notes afterwards, use the interview synthesis skill.

Common mistakes

• Pitching instead of listening. Once you pitch, you get compliments.
• Counting "I'd buy that" as a sale. Only a commitment counts.
• Asking about the future. People are bad at predicting their own behavior.
• Talking to anyone who'll talk. A vague segment gives mixed signals.

Where it comes from

Rob Fitzpatrick, a founder and Y Combinator alumnus who moved from programming into customer-facing work, wrote The Mom Test as a practical handbook. It is sold in print and as a PDF from the book's site, and is available in several languages.

This page is an independent summary in our own words. It is not affiliated with or endorsed by Rob Fitzpatrick. The book's title is used only to name it. More explainers are in the business books index.

Questions

What is the Mom Test?

A way of asking about customers' lives and past behavior so that even someone who wants to be nice to you, like your mom, can't mislead you about whether your idea is good.

What are the three rules of the Mom Test?

Talk about their life instead of your idea. Ask about specifics in the past instead of generics or opinions about the future. Talk less and listen more.

What counts as a good outcome from a customer conversation?

Facts about how they handle the problem today, and a commitment that costs them something: time for a next meeting, an introduction, a pilot or a pre-order. Compliments don't count.