Chapter 4 of 9

Chapter 4: Quantitative Verification

Statistical rigor, surveys, and pricing psychology methodologies.

Playbook Chapters
What You'll Learn By the end of this chapter, you'll know how to turn qualitative insights into quantitative evidence, use the Sean Ellis Test to measure product-market fit, and test pricing before you build anything.

From Stories to Numbers

Interviews tell you why. Surveys tell you how many. You need both.

Qualitative discovery gives you insight—the stories, emotions, and context behind customer behavior. Quantitative verification gives you evidence—proof that these patterns exist at scale.

Qualitative

"5 out of 8 interviewees mentioned frustration with manual data entry."

Tells you: What the problem is and why it hurts.

Quantitative

"47% of respondents ranked data entry as their #1 time waster."

Tells you: How widespread the problem is.

The Numbers-Without-Context Trap

Quantitative data without qualitative context is dangerous. Knowing that 40% of users churn is useless if you don't know why. Always pair numbers with understanding.

The Sean Ellis Test (Product-Market Fit)

Sean Ellis, who coined "growth hacking," created the most widely-used measure of product-market fit. It's one question:

The Question

"How would you feel if you could no longer use [product]?"

  • Very disappointed
  • Somewhat disappointed
  • Not disappointed

<40%

Very disappointed

No PMF. Keep iterating.

40-50%

Very disappointed

On the edge. Focus on delighting this segment.

>50%

Very disappointed

Strong PMF. Time to scale.

Pricing Research: Test Before You Build

Pricing isn't an afterthought—it's a product feature. You must test pricing early to understand if your business model is viable. For deeper pricing strategy, see Playbook 05: Pricing Strategy.

Van Westendorp Price Sensitivity Meter

Ask four questions to find your acceptable price range:

Question What It Measures
"At what price would it seem so cheap that you'd question quality?" Too Cheap (floor)
"At what price would it feel like a bargain?" Cheap (value perception)
"At what price does it start to feel expensive?" Expensive (resistance begins)
"At what price would it be too expensive to consider?" Too Expensive (ceiling)
Simpler Alternative: Gabor-Granger

"Would you buy at $X?" If yes → ask higher price. If no → ask lower price. Repeat until you map the demand curve. Works well for early-stage testing.

Survey Design Principles

Bad surveys lead to bad decisions. Here's how to avoid common mistakes:

Bad Questions

  • Leading: "Don't you agree that our tool saves time?"
  • Compound: "Is it fast and easy to use?"
  • Hypothetical: "Would you use this if we built it?"
  • Vague: "How satisfied are you?"

Good Questions

  • Neutral: "How would you rate the speed?"
  • Single: "Is it fast?" (separate from "Is it easy?")
  • Behavioral: "How many times did you use X last week?"
  • Specific: "How satisfied are you with the export feature?"

Statistical Reality Check

Don't be fooled by small sample sizes.

The Small Sample Trap

If 2 out of 3 people say yes, that's not 66%. That's statistical noise. With 3 responses, your margin of error is ±40%.

Rule of thumb: For directional accuracy, aim for 30+ responses. For confident decisions, aim for 100+.

What You Walk Away With

  • Sean Ellis Score: A number that tells you if you have product-market fit.
  • Pricing Validation: Evidence of what customers will actually pay.
  • Survey Results: Quantitative proof that your qualitative insights scale.
  • Statistical Awareness: Understanding of your margin of error.
Build Your Survey

Design surveys that avoid bias and generate actionable quantitative insights with our AI-powered Survey Builder.

Insight Survey Builder
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Works Cited & Recommended Reading
Lean Startup & Innovation Accounting
Assumption Mapping & Testing
  • 7. Invest in Winning Ideas with Assumption Mapping. Miro
  • 10. Testing Business Ideas: Book Summary. Strategyzer
  • 11. Innovation Tools – The Assumption Mapper. Nico Eggert
  • 14. Business Testing: Is your Hypothesis Really Validated? Strategyzer
  • 16. An Introduction to Assumptions Mapping. Mural
  • 17. Assumption Mapping Techniques. Medium
Customer Interviews & The Mom Test
  • 8. Book Summary: The Mom Test by Rob Fitzpatrick. Medium
  • 22. The Mom Test for Better Customer Interviews. Looppanel
  • 23. The Mom Test by Rob Fitzpatrick [Actionable Summary]. Durmonski.com
  • 9. How to Evaluate Customer Validation in Early Stages. Golden Egg Check
Jobs-to-Be-Done Framework
  • 24. Jobs to be Done 101: Your Interviewing Style Primer. Dscout
  • 25. How To Get Results From Jobs-to-be-Done Interviews. Jobs-to-be-Done
  • 26. A Script to Kickstart JTBD Interviews. JTBD.info
Product-Market Fit & Surveys
  • 33. Sean Ellis Product Market Fit Survey Template. Zonka Feedback
  • 34. How to Use the Product/Market Fit Survey. Lean B2B
  • 35. Product Market-Fit Questions: Tips and Examples. Qualaroo
  • 36. Product/Market Fit Survey by Sean Ellis. PMF Survey
Pricing Validation Methods
Smoke Tests & Fake Door Testing
  • 43. Smoke Tests in Market Research - Complete Guide. Horizon
  • 45. Fake Door Testing - How it Works, Benefits & Risks. Chameleon.io
  • 52. High Hurdle Product Experiment. Learning Loop
  • 53. Fake Door Testing: Measuring User Interest. UXtweak
Conversion Benchmarks & Metrics
  • 46. Landing Page Statistics 2025: 97+ Stats. Marketing LTB
  • 47. Understanding Landing Page Conversion Rates 2025. Nudge
  • 49. What Is A Good Waitlist Conversion Rate? ScaleMath
  • 54. Average Ad Click Through Rates (CTRs). Smart Insights
Decision Making & Kill Criteria
  • 57. From Test Results to Business Decisions. M Accelerator
  • 58. Kill Criteria for Product Managers. Medium
  • 59. When to Kill Your Venture - Session Recap. Bundl

This playbook synthesizes research from Lean Startup methodology, Jobs-to-Be-Done theory, behavioral economics, and validation frameworks. Some book links may be affiliate links.