November 15, 2021 ~ 9 min read

The Mom Test: Book Notes


The Mom Test is the best book I've read on how to actually talk to your customers (and potential customers) in a way that will help you build the right thing. 5/5 ⭐ overall.

This is a must read for aspiring product people, as well as founders.

The YCominator tag line is "Make something people want", but we rarely talk about how to actually do that. I think most great companies are started with a key insight (top down, rather than bottom up), but even once you have this insight - you need to have a way of validating it.

The natural tendency when trying to validate one of these ideas, is to ask people what they think of it. This turns out to be terrible advice. People will lie to you. Not because they mean to, but because they want to protect you.

In many ways, this book is an extension of Taleb's Skin in the Game. Don't ask people what they think, ask them what they do.

That's where the mom's test comes in.

Chapter 1: The Mom Test

"The Mom Test:

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

It's called The Mom Test because it leads to questions that even you mom can't lie to you about."

Not only is this a great litmus test, it's also catchy enough that you can easily remember it and share it with their team.

A few other great litmus tests that the book offers up:

"The measure of usefulness of an early customer conversation is whether it gives us concrete facts about our customers' lives and world views"

"the big mistake is almost always to mention your idea too soon rather than too late. If you just avoid mentioning your idea, you automatically start asking better questions. Doing this is the easiest (and biggest) improvement you can make to your customer conversations."

"Rule of thumb: Some problems don’t actually matter."

^ I think this rule of thumb is where many folks go wrong, particularly early in their careers (I've been there)

"Rule of thumb: Watching someone do a task will show you where the problems and inefficiencies"

"Rule of thumb: If they haven't looked for ways of solving it already, they're not going to look for (or buy) yours."

"Rule of thumb: People want to help you. Give them an excuse to do so."

I think a lot of these rules are things that we know, but that we don't always follow. And that's because it's hard. Understanding these rules is only the first step, applying them in practice is the only step that matters.

Chapter 2: Bad Data

This chapter focuses more on how to do no harm and avoid common pitfalls.

"There are three types of bad data:

  1. Compliments
  2. Fluff (generics, hypotheticals, and the future)
  3. Ideas"

"Rule of thumb: Compliments are the fool’s gold of customer learning: shiny, distracting, and worthless."

The world’s most deadly fluff is: “I would definitely buy that.”

"While using generics, people describe themselves as who they want to be, not who they actually are. You need to get specific to bring out the edge cases."

"Startups are about focusing and executing on a single, scalable idea rather than jumping on every good one which crosses your desk."

^ This one is not super relevant to a book, but it's a good reminder.

"Rule of thumb: Ideas and feature requests should be understood, but not obeyed."

^ Every enterprise software company needs to have this one written on their wall

"Rule of thumb: If you’ve mentioned your idea, people will try to protect your feelings."

"Rule of thumb: The more you’re talking, the worse you’re doing."

Chapter 3: Asking Important Questions

Now that we know the rules of the game, we have to figure out how to actually get to the important stuff. After reading chapter 2, I think it's tempting to want to tiptoe around what we actually want to get at because we want to avoid making a mistake. This chapter helps us get over that.

"Every time you talk to someone, you should be asking at least one question which has the potential to destroy your currently imagined business."

"Rule of thumb: You should be terrified of at least one of the questions you’re asking in every conversation."

If you just read these 3 chapters, I think you'd get 80% of the value from the book. That said, I think the others are still worth reading, just because they are a topic that is so often overlooked. I think the first 3 chapters apply to anyone conducting user interviews, whereas the others are more applicable for the specific case of starting a new company.

Chapter 4: Keeping it Casual

"Rule of thumb: Learning about a customer and their problems works better as a quick and casual chat than a long, formal meeting."

Probably my favorite takeaway from this book is that conversations are often more valuable than user interviews that were formally set up. Conversations are a land mine for startup ideas. Listening and being interested in other people can yield a lot of good ideas.

Chapter 5: Commitment and Advancement

You had your first meeting with a potential customer. Now what?

"Once we've learned the key facts about our industry and customers, it’s time to zoom in again and start revealing our idea and showing some product. The bad news is that this invites nefarious compliments. The good news is that since we have the beginnings of a product, we’re now in a position to cut through the false positives by asking for commitments."

"Rule of thumb: “Customers” who keep being friendly but aren’t ever going to buy are a particularly dangerous source of mixed signals."

"It took me years to learn that there’s no such thing as a meeting which just “went well”. Every meeting either succeeds or fails. You’ve lost the meeting when you leave with a compliment or a stalling tactic."

"Rule of thumb: If you don’t know what happens next after a product or sales meeting, the meeting was pointless."

"Rule of thumb: The more they’re giving up, the more seriously you can take what they’re saying."

"Rule of thumb: It’s not a real lead until you’ve given them a concrete chance to reject you."

"Steve Blank calls them earlyvangelists (early evangelists). In the enterprise software world, they are the people who: Have the problem Know they have the problem Have the budget to solve the problem Have already cobbled together their own makeshift solution"

Chapter 6: Finding Conversations

This is about actually executing on the content in the book. How do you actually find people to talk to?

"Rule of thumb: If it’s a topic you both care about, find an excuse to talk about it. Your idea never needs to enter the equation and you’ll both enjoy the chat."

How to structure an email:

"The framing format I like has five key elements.

  1. You’re an entrepreneur trying to solve horrible problem X, usher in wonderful vision Y, or fix stagnant industry Z. Don’t mention your idea.
  2. Frame expectations by mentioning what stage you’re at and, if it’s true, that you don’t have anything to sell.
  3. Show weakness and give them a chance to help by mentioning the specific problem that you’re looking for answers on. This will also clarify that you’re not a time waster.
  4. Put them on a pedestal by showing how much they, in particular, can help.
  5. Explicitly ask for help."

"If you’re banging your head against the wall trying to get people to answer your cold emails, then you’re probably taking the hard road. Spend your energy finding clever ways to generate warm intros instead. You’ll have a much easier time."

Chapter 7: Choosing Your Customers

This chapter is pretty standard material for anyone that's ever worked at a moderately successful startup. Focus is key.

"They say that startups don’t starve, they drown. You never have too few options, too few leads, or too few ideas; you have too many. You get overwhelmed. You do a little bit of everything. When it comes to getting above water and making faster progress, good customer segmentation is your best friend."

"Rule of thumb: If you aren’t finding consistent problems and goals, you don’t have a specific enough customer segment."

Chapter 8: Running The Process

This chapter has some helpful info about actually running a user interview process, but I think the right process will look quite different depending on the stage of company you're operating under. Most of this content is relatively straight-forward, and I think through trial and error you can pretty quickly come to a solid process, even without reading this chapter.

"When all the customer learning is stuck in someone’s head instead of being disseminated to the rest of the team, you’ve got a learning bottleneck. Avoid creating (or being) the bottleneck. To do that, the learning must be shared with the entire founding team promptly and faithfully, which depends on good notes plus a bit of pre- and post-meeting work."

Symptoms of a learning bottleneck:

  • “You just worry about the product. I’ll handle the customers.”
  • “Because the customers told me so!”
  • “I don’t have time to talk to people — I need to be coding!”

"Rule of thumb: If you don’t know what you’re trying to learn, you shouldn’t bother having the conversation."


Maxi Ferreira

Hi, I'm Taylor . I'm a software engineer/maker/amateur chef currently living in San Francisco. You can follow me on Twitter , see some of my work on GitHub , or read about my life on Substack .