The Mom Test

Why your mom is the wrong judge

Ask your mom whether your business idea is good and she'll say yes. She loves you and doesn't want to hurt your feelings. The problem is that almost everyone acts like your mom when you pitch them an idea. Saying something nice is easy; telling you the idea won't work is awkward.

Rob Fitzpatrick's book The Mom Test, published in 2013, starts from that problem. Its point is simple: it's your job to ask questions that can't be answered with a polite lie. If you do, even your mom will give you useful answers. If you don't, a hundred interviews will only tell you what you want to hear.

The three rules

1. Talk about their life, not your idea

Once you describe your idea, people start reacting to it, and reactions are mostly politeness. Ask about their work, their week and the problem instead. Save the pitch for the end, or skip it.

2. Ask about specifics in the past, not the future

“Would you use this?” asks for a guess. “When did this last happen, and what did you do?” asks for a fact. People are bad at predicting what they'll do and good at describing what they did.

3. Talk less, listen more

If you're talking, you're not learning. Ask a short question, then let the silence run. The useful detail usually comes in the second or third sentence of an answer.

Good questions to ask

Each of these asks about something that already happened, or about what the problem costs, so the answer is a fact you can use. Several come straight from the book.

• “Talk me through the last time that happened.”
• “What did you do about it? What else have you tried?”
• “Why do you bother?” It shows what they're really trying to get done.
• “What are the implications of that?” It separates a costly problem from a small annoyance.
• “How are you dealing with it now?”
• “Where does the money for that come from?”, for business tools.
• “Who else should I talk to?”
• “Is there anything else I should have asked?”

Bad questions to avoid

“Do you think it's a good idea?”

Only the market can tell you that. Opinions are cheap; behavior isn't.

“Would you buy a product that did this?”

A hypothetical with an easy, polite answer. People say yes and then don't buy.

“How much would you pay for it?”

The same problem with a number attached. Test price with a real offer instead.

“What would your dream product do?”

A wish list is a guess. Ask why they want each feature: the reason behind it is what you need.

Three kinds of bad data

Even with good questions, conversations drift. Fitzpatrick names three kinds of answers to catch and steer away from:

Compliments

“That sounds great!” feels like progress and means nothing. Thank them, and go back to asking about their life.

Fluff

Generic or future statements: “I usually…”, “I always…”, “I would definitely…”. Ask for the last specific time instead.

Ideas and feature requests

Write them down, then ask what problem the feature would solve and how they handle it today.

Commitment: how to tell if a meeting went well

A good conversation ends with the other person giving up something: time, reputation or money. Agreeing to a second meeting, introducing you to their boss, trying an early version or paying a deposit all count. A warm goodbye and “keep me posted” doesn't.

If every meeting ends with compliments and no next step, you're collecting polite lies. Ask for something concrete at the end, like a trial, an introduction or a pre-order, and see who says yes.

Start with what people already wrote

The rules are easier to follow when the other person brought up the problem first. Public posts where people ask for help are unprompted descriptions of past behavior: exactly what a good interview tries to draw out. Read them before your calls and you'll know which questions to ask and which words people use.

These posts, from our ideas library, are from people trying to stop losing hours to their phone. The third is the kind of insight a good interview finds: the hard part isn't setting limits, it's keeping them.

Find posts about your idea with the free idea validator

How many interviews you need

There's no magic number, but you'll usually notice the same answers repeating after five to ten conversations with people in one group. If the answers are all over the place, your group is too broad: narrow it and start again.

Interviews have a limit. They tell you whether a problem is real and how people describe it. They can't tell you whether people will pay, because nothing is at stake in a conversation. For that, put a real offer in front of them, such as a landing page with a price.

How to run a landing page test