The PMF Measurement Guide

Product-market fit (PMF) is the degree to which a product satisfies strong market demand. Marc Andreessen famously described it as “being in a good market with a product that can satisfy that market.”

But how do you measure it? For years, PMF was treated as something you “just know” when you have it. That changed when Rahul Vohra, CEO of Superhuman, developed a systematic, survey-based approach to quantify PMF — and used it to methodically improve their product until they achieved it.

The Core Question: The Sean Ellis Test

The foundation of the PMF methodology is a single question, originally proposed by Sean Ellis:

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

a) Very disappointedb) Somewhat disappointedc) Not disappointed

Your PMF score is the percentage of users who answer “Very disappointed.”

The 40% Benchmark

After surveying hundreds of startups, Sean Ellis found that companies where 40% or more of surveyed users said they'd be “very disappointed” consistently went on to build sustainable growth. Below 40%, companies struggled to scale efficiently.

This benchmark has been validated across hundreds of startups and is now the industry standard for measuring PMF.

Rahul Vohra expanded the single Ellis question into a 7-question survey that not only measures PMF but tells you what to do about it:

1. How would you feel if you could no longer use [product]?
   The core PMF metric — your headline score.
2. What type of people do you think would most benefit from [product]?
   Identifies your ideal customer persona in the user's own words.
3. What is the main benefit you receive from [product]?
   Reveals your product's core value proposition — as perceived by users.
4. How can we improve [product] for you?
   Direct improvement suggestions from your most engaged users.
5. What would you likely use as an alternative if [product] were no longer available?
   Maps your competitive landscape from the user's perspective.
6. Have you recommended [product] to anyone?
   Measures organic advocacy and word-of-mouth potential.
7. How did you first discover [product]?
   Reveals which acquisition channels actually work.

Segment by Persona

Don't just look at the overall score. Break responses down by customer type. You may find that your PMF score is 25% overall, but 60% among a specific segment. That segment is your beachhead — double down on serving them.

Read the Word Clouds

Questions 3 and 4 generate word clouds of benefits and improvement requests. The key insight: focus on what “very disappointed” users love (Q3), and address what “somewhat disappointed” users want improved (Q4). This is the fastest path to converting “somewhat” into “very” disappointed.

Track Over Time

PMF is not a one-time measurement. Survey regularly (quarterly is a good cadence) and track your score over time. Each product improvement should move the needle.

Rahul Vohra's framework for systematically improving PMF:

1. Segment: Find the users who already love you (“very disappointed” group). Study their persona, use case, and what they value most.
2. Analyze: Read what “somewhat disappointed” users wish was better. These are the improvements most likely to convert them into power users.
3. Build: Prioritize features that strengthen what power users love AND address what on-the-fence users want. Ignore requests from “not disappointed” users — they're likely not your target market.
4. Re-measure: After shipping improvements, survey again. If your score goes up, you're on the right track. If not, iterate.

How Many Responses Do You Need?

For statistically meaningful results, aim for at least 40 responses. Below that, your score may fluctuate significantly with each new response. With 100+ responses, you can confidently segment by persona and track trends.

Send surveys to users who have used your product enough to have an informed opinion — typically those who have been active for at least 2 weeks.

Further Reading

• How Superhuman Built an Engine to Find Product-Market Fit — Rahul Vohra's original article on First Round Review
• The Startup Pyramid — Sean Ellis's original framework