Rob Fitzpatrick · momtestbook.com
If you ask your mum whether your business idea is good, she'll say yes. Not because it is, but because she loves you and doesn't want to hurt your feelings. The same thing happens with friends, colleagues, and even potential customers. People are polite. They'll tell you what you want to hear, not what you need to hear. The Mom Test, written by Rob Fitzpatrick, is a set of rules for crafting questions so good that even your mum can't lie to you about them.
The core insight is brutally simple: stop talking about your idea and start talking about their life. Instead of "would you use an app that does X?", ask "tell me about the last time you dealt with this problem." Instead of "how much would you pay?", ask "how much does this cost you today in time or money?" The difference is enormous. The first set of questions invites people to be polite. The second set forces them to recall concrete facts from their actual experience.
Fitzpatrick identifies three deadly sins of customer conversations: seeking compliments ("don't you think this is great?"), dealing in hypotheticals ("would you ever...?"), and talking too much about yourself. The antidote is to ask about specific past behaviour, listen far more than you speak, and actively seek reasons your idea might not work. If every conversation leaves you feeling great about your idea, you're doing it wrong.
The Mom Test shapes every question Distil asks, across all phases. It's the most pervasive framework in the system because it governs how questions are asked, not just what is asked. When you make a claim about your customers, Distil pushes for concrete evidence. "You said small businesses struggle with invoicing. Can you tell me about a specific conversation where someone described that struggle to you?"
During the warmup phase, the Mom Test is one of two primary frameworks (alongside JTBD). Distil never asks "is this a good idea?" because the answer is always yes and always meaningless. Instead, it asks about your direct experience with the problem, who you've spoken to, and what you've observed in the real world.
In later phases, the Mom Test acts as a quality filter. When you claim there's demand, Distil asks for behavioural evidence, not opinions. "Ten people said they'd buy it" scores lower than "three people pre-ordered." This distinction directly feeds into all three scoring dimensions: Problem Clarity, Solution Potential, and Idea Maturity.
Distil applies Mom Test principles to every question, so you get truth, not politeness.
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