Mom Test Questions: 26 Bad vs Good Examples

A common mistake during customer interviews is to ask things like "Would you use this?", which, unsurprisingly, you can guess the answer to: yes. Saying it costs the other person nothing, and it tells you nothing about whether they will pay.

If you want to avoid that, ask Mom Test questions instead. This post contains 26 of them, each next to the bad version of the question. I sorted them by the type of information you need, and if you only have time for a few, start with questions 1, 8, 14, 22 and 25.

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What is the Mom Test?

The Mom Test is a set of rules on how to talk to your customers that comes from the book The Mom Test by Rob Fitzpatrick, published in 2013. The name comes from the idea that your mom will want to tell you that what you’re doing is great, so you should be asking questions that even she cannot lie to you about.

Fitzpatrick is a programmer and a Y Combinator alum who found himself talking to customers at his first company, without any book that would teach him how to do that. The Mom Test contains three rules which, rephrased by me, are:

1. Ask about their life instead of your idea.
2. Ask about specifics in the past instead of general or future-oriented questions.
3. Talk less and listen more.

Most bad customer interview questions break the second rule, so, as a rule of thumb, you can just remember:

"Anything involving the future is an over-optimistic lie."

So ask about past behavior and real spending. Don’t ask about their opinions on your idea or about what they will do once you have a product.

What makes a good Mom Test question?

Before I keep a question, I check that it is about their life and not my idea, and that it points at one specific moment that already happened. The answer should cost them a little effort to give: a date, a count, someone’s name. If you can guess the answer before the call, the question goes.

The book splits all the bad data you can get from asking the wrong questions in three categories: compliments, fluff (that includes generic claims, hypotheticals and future promises) and ideas (that are, in reality, feature requests, since they don’t explain the why behind them). I’ll describe the problem with each bad question below.

The book is not as hard as it might seem from the description above and actually says that you don’t need to avoid asking "would you ever" questions completely, as they can be good for starting a conversation about a topic. The trouble starts when you write the answer down as evidence.

If you feel the answer is too vague, ask additional questions to get the person to talk in facts, such as "When was that?", "Can you show me?", "What did you do next?" or "What did it cost?". At the end of the call, before you hang up, ask the question the book itself suggests: "Is there anything else I should have asked?"

Source: my own set of 26 question pairs, built on the three rules and the three kinds of bad data in Rob Fitzpatrick’s The Mom Test (2013), official site read October 12, 2026. The table sorts questions by goal; it measures nothing.

This page explains what you should ask during your Mom Test calls. For how to find people and run the call, check out my separate guide.

Which Mom Test questions prove the problem is real?

Here are a few examples of good problem questions to ask when applying the Mom Test. When I say good, I mean they’ll help you find out if a problem actually exists or not. Most people will agree with you if you tell them what their pain is. Instead, ask them when it last happened.

A common mistake is asking a question that’s too broad, which will result in a very generic answer that doesn’t help you. This happened to someone from r/startups who asked about the biggest challenge of the last few weeks and ended up with answers that were as generic as the question. One reply summed it up: "Ask generic questions, get generic answers." Instead, choose the area beforehand and then ask about the last time something happened in it, which gives you a more specific answer.

Which questions uncover what they do about it today?

These Mom Test workaround questions find out what the real competition is (it’s usually not a product). In other words, what is the workaround? Workarounds are a strong signal of pain, because the customer is already paying for them with their time.

Watch out for the third type of bad data in these questions, namely feature requests. If it happens, dig deeper into why they are asking for this feature, as the book explains.

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How do you ask about money without asking what they would pay?

It can feel rude to ask about spending, but it’s important to ask about it. It’s tempting to ask "How much would you pay?", but the book shows why this is as bad as asking "Would you buy it?"

Instead, I recommend asking how much the problem is costing them (in money, hours or people), and how much they are paying for anything that solves part of the problem. This gives you something to compare your product to when you set a price, and something you can check is real. Asking people how much they would pay for a product that doesn’t exist yet gives you something you can’t check.

Which Mom Test questions show who buys?

"You need to talk to the person who signs checks." That line, from a post on r/SaaS about B2B, is the reason this group exists.

I guess the best way to ask this is “how was the last thing you bought to do X bought?”, because it’s the most recent example of somebody buying a tool like this and so it’s the best guide you’ve got to how this will be bought. It should also give you an idea of whose credit card the thing will come out of. If it’s fairly straightforward (the person who has the problem just buys it on their own credit card, like a personal trainer running their own practice) then 22 and 23 should be enough.

What mistakes ruin a Mom Test interview?

There are 5 mistakes you don’t know you’re making while you make them, and they make your notes look like validation of what you wanted to hear in the first place.

• You pitch too early. The Mom Test says founders almost always mention the idea too soon, not too late. Once you pitch, they start rating your idea instead of describing their week, and you can’t go back.
• You ask hypothetical questions. Phrases like "Would you…", "Could you see yourself…" or "Would you buy…" all ask for a prediction.
• You count compliments as validation. In a Hacker News discussion of the book, a commenter described a founder whose plan rested on businesses saying they would buy. The commenter told her to ask each one for a refundable check. "Not one gave her money."
• You ask leading or yes-or-no questions. Another interesting comment on the same Hacker News thread was about a trick blind people are taught when they catch a tram and want to know if it’s the one they’re looking for. They ask "which line is this?", never "is this line 4?", because people tend to answer yes out of reflex to the second question. Same goes for the questions you will ask during your Mom Test interviews.
• You talk too much, which breaks the third rule of the Mom Test. Remember to stay silent for a few seconds after short answers, as this is often when the real information comes out.

But there is a 6th mistake that you won’t be making during the interviews, and it can invalidate a lot of them even if you do them perfectly: asking questions you could have answered on your own, wasting your interviewees’ time. It’s also one way to fall into confirmation bias in startup validation: only asking questions you already know the answer to.

What should you check before your first interview?

Interviews are expensive, especially if you’re doing them for the first time and don’t have an audience yet. So before the first ones, make sure to check everything you can check publicly: who your potential competitors are (who is already selling to your potential buyers?), how much they charge, and whether there is a market at all.

Let’s say you want to develop an app that would help independent personal trainers manage their booking and payments. Here is what public pages tell you before a single call:

Source: U.S. Bureau of Labor Statistics, Occupational Outlook Handbook, Fitness Trainers and Instructors; ABC Trainerize pricing and TrueCoach pricing; all read October 12, 2026. The BLS figure counts jobs, not businesses or software buyers.

As you can see in the market row, many personal trainers are not independent but work for gyms and studios, where the decision to buy software will probably not be taken by the trainers themselves. And the price row says a trainer can try either tool without paying: a one-client free plan or a 14-day trial.

This way, you can skip questions like "Are there trainers or software for this already?" and go straight to what no public page can answer: whether this trainer has the pain, what they pay now, and who signs.

I built Preuve’s free idea validation check for this part, and you can run it before your first call. Just scan your idea: in less than a minute, it checks 60+ live data sources and gives you a score with the main risks of your idea and a first look at your competitors. What they charge you still read off their pricing pages, as above. In my benchmark study, based on anonymized data from 6,000+ ideas, 17.5% got a clear go, so it’s likely your idea will also have some risks. And that’s ok! You can use these risks to guide your first calls: if one of them is about competition, focus on questions 8 and 10; if it’s about willingness to pay, focus on questions 14 and 15. Run the free check on your idea before you book the first call.