Mom Test Interview Discipline
Position in workflow: v1.0 Continuous Discovery (Torres) → v1.0 Mom Test Interview → v1.0 Case Study Builder, Testimonial Collector
Execution Mode
Default is standard. See .claude/rules/08-skill-execution-modes.md for selection logic.
| Mode | What this skill produces |
|---|---|
| quick | Single interview prep + question list + CFD-* discovery entry post-interview |
| standard | Interview prep + scripted opening + 5–7 questions + CFD-* entry with confidence calibration + Bad Data flagged |
| deep | Multi-interview cohort plan + cross-interview synthesis + pattern flagging at 3-mention threshold + assumption-test handoff |
Framework: The Mom Test
From The Mom Test: How to Talk to Customers and Learn If Your Business is a Good Idea When Everyone is Lying to You (Rob Fitzpatrick, 2013). Premise: People lie to spare your feelings — especially about your business idea. Learn to ask questions that get truth.
The three Mom Test rules
- Talk about their life, not your idea. Ask about how they actually live and work, not whether they'd like your hypothetical feature.
- Ask about specifics in the past, not generics or opinions about the future. "Last time you faced X, what did you do?" beats "Would you use a tool that does Y?"
- Talk less and listen more. If you're talking more than 30% of the time, you're pitching, not learning.
Three types of Bad Data to avoid
| Bad Data type | Example | Why it's bad | What to do |
|---|---|---|---|
| Compliments | "That sounds awesome!" | Politeness; not predictive | Discard; don't update confidence |
| Fluff | "I usually..." "I would probably..." | Generics, future hypotheticals | Anchor to specifics: "When did you last do that?" |
| Ideas | "You should add X" | Solution suggestions disguised as needs | Note as IDEA; ask "what would solving X enable you to do?" — get the underlying job |
Confidence calibration
Mom Test-disciplined interviews produce higher-confidence CFD- entries because the data is grounded in observed past behavior, not opinion. Confidence floors per P4:
- 2/5 — Generic statement ("I sometimes have this problem")
- 3/5 — Specific past instance ("Last Tuesday, I spent 2 hours doing X")
- 4/5 — Specific past instance + paid-money-for-a-workaround / hired-a-person / built-a-script ("I'm paying $30/mo for a tool that almost solves this")
- 5/5 — Repeated specific past instances + ongoing willingness to invest in better solution (commit > talk)
Consumes
- ADO-BEACHHEAD-* and PER-* personas — Defines the interview pool; non-segment interviews are still useful but get lower weight
- Opportunity Solution Tree (from prd-v10-continuous-discovery-torres) — Interview goals trace to specific opportunities being tested
- CFD-* prior research — Patterns to validate or contradict
- KPI-* outcomes — Why we're interviewing (anchor to what we're trying to move)
Produces
- CFD-* discovery interview entries — One per interview, with confidence calibrated by Mom Test rules
- CFD-* pattern entries — When 3+ interviews mention the same specific behavior, promote to a pattern entry with frequency
- Bad Data inventory — Compliments, fluff, ideas captured for context but not data
- Discovery Tree updates — Each interview either strengthens an opportunity, weakens an opportunity, or surfaces a new one
Execution
Step 1: Define the goal of this interview
Not "validate the idea." Specifically: which opportunity / assumption from the Opportunity Solution Tree is this interview testing?
| Goal | Example |
|---|---|
| Validate opportunity exists | "Do beachhead pragmatists actually struggle with pricing-tier selection?" |
| Test assumption | "Will users engage with a pricing wizard before signup?" |
| Map workaround | "How are they solving this today?" |
| Quantify pain | "How much time/money does this cost them currently?" |
Write the goal at the top of the interview notes.
Step 2: Prep the question list (Mom Test-shaped)
Use specifics-in-the-past form. Avoid hypotheticals.
| Bad question | Better (Mom Test) version |
|---|---|
| "Would you use a pricing wizard?" | "Walk me through how you picked the tier when you signed up." |
| "Do you think analytics is important?" | "Tell me about the last time you looked at analytics." |
| "What features do you wish we had?" | "Tell me about the last time the tool didn't do what you needed." |
| "How would you describe X?" | "Tell me about the last time X came up at work." |
5–7 questions is plenty for a 25–30 minute interview. Leave room to follow threads.
Step 3: Run the interview
- Open with a short framing: who you are, why this conversation, no sales pitch
- Ask the past-behavior questions, listen, follow threads
- Probe specifics when they generalize: "When was that specifically?" / "What was the dollar / time cost?" / "What did you do next?"
- Flag Bad Data internally: when they compliment, smile and move on; when they fluff, anchor to specifics; when they suggest ideas, note as IDEA and dig for the underlying job
- Talk less than 30% of the total minutes
- Don't pitch. If they ask what you're building, give a one-sentence answer and pivot back
Step 4: Write up the CFD-* entry within 4 hours
Memory decays fast. Within 4 hours of the interview, write up the CFD- entry. Include:
- Verbatim quotes (the best evidence)
- Specific past instances (the gold)
- Bad Data inventory (compliments, fluff, ideas) — kept for context but not counted as data
- Confidence per P4 calibration
Step 5: Update the Opportunity Solution Tree [standard+]
Did this interview:
- Strengthen an existing opportunity (add to frequency count)?
- Contradict an existing opportunity (note dissenting evidence)?
- Surface a new opportunity (add to tree)?
Promote a pattern to "Active" focus when 3+ interviews mention the same specific behavior.
Step 6: Cross-interview synthesis [deep only]
After every cohort of 5–8 interviews, synthesize:
- What patterns emerged at the 3+ mention threshold?
- What hypotheses were contradicted?
- What new opportunities surfaced?
- What's the next interview cohort target?
Output Template
CFD-XXX: Mom Test Interview — [Brief title] Type: Discovery-Interview Date: YYYY-MM-DD Length: [minutes] Interviewee: [PER-XXX + in-beachhead: yes/no] Interviewer: [Name] Goal: [Specific opportunity/assumption being tested] Specific past instances captured (the gold): - "[Verbatim quote — describes a specific past behavior]" Context: [When, where, what they did, what it cost] Confidence: 3/5 or 4/5 (per P4 calibration) Workarounds observed: - [What they currently do; tools/spend/time invested] Bad Data (logged but not counted): - Compliments: ["That sounds awesome"] - Fluff: ["I'd probably use that"] - Ideas: ["You should add X"] → underlying job: [What X would enable] Pattern strengthening: - O1 [opportunity]: +1 mention (now N total) New opportunity surfaced (if any): - [Description] Overall confidence of this interview's data: X/5 Linked IDs: PER-XXX, ADO-BEACHHEAD-XXX, KPI-XXX, Opportunity-Tree-Node
Anti-Patterns
| Pattern | Signal | Fix |
|---|---|---|
| Pitching disguised as interview | Interviewer talking >40% of the time | Talk less; ask follow-ups; let silence happen |
| Future-hypothetical questions | "Would you use..." | Reframe to past-behavior |
| Treating compliments as data | "5 people said it sounds great → strong signal" | Compliments are not data; discount |
| Recording feature requests as opportunities | "User asked for dark mode → opportunity: dark mode" | Dark mode is a solution; the opportunity is the underlying job (e.g., late-night use, eye strain) |
| No specifics-probe | Interview ends without a single "what specifically" follow-up | Build the habit; specifics are the gold |
| Writing up days later | Interview Friday, CFD- entry Monday | Memory decays; write within 4 hours |
| No goal for interview | "Just talking to users" | Each interview tests one specific opportunity or assumption |
| All interviews from outside beachhead | Strong patterns but not in segment | In-segment interviews dominate; out-of-segment is supplementary |
Quality Gates
For each interview:
- Goal stated before interview (which opportunity/assumption is being tested)
- Question list is past-behavior shaped, not hypothetical
- Interviewer talked <30% of minutes
- At least one "what specifically" follow-up was asked
- Bad Data inventory exists (compliments / fluff / ideas — even if empty)
- CFD- entry written within 4 hours
- Confidence per P4 calibration (not "feels good")
- Discovery Tree updated (pattern strengthen / contradict / new opportunity)
Downstream Connections
| Consumer | What it uses | Example |
|---|---|---|
| Continuous Discovery (Torres) | Every interview updates the Opportunity Solution Tree | This skill is the how; Torres is the what to do with |
| Chasm Adoption (Moore) | In-beachhead interviews update ADO-STAGE-* and ADO-BEACHHEAD-* | Patterns strengthen stage assessment |
| Case Study Builder | High-impact interviewees become case-study candidates | CFD- with 5/5 confidence + outcome → ADO-REF-* |
| Testimonial Collector | Strong endorsement interviews become testimonial sources | Specific past-instance quote + consent → testimonial |
| Feedback Loop Setup | Mom Test is the discipline for the structured-interview arm | Inbound feedback ≠ Mom Test (still useful, lower confidence) |
Detailed References
- Rob Fitzpatrick, The Mom Test (2013) — canonical source, short and readable
- Rob Fitzpatrick, The Workshop Survival Guide (companion)
- Steve Portigal, Interviewing Users (complementary depth)
- wondelai's
mom-testskill (wondelai/skills) - (No bundled
references/— read the book; it's 130 pages)

