product-market-fit

# Product-Market Fit

Frameworks for measuring, achieving, and maintaining the critical milestone where your product satisfies strong market demand.

## Overview

Product-Market Fit (PMF) is the degree to which a product satisfies strong market demand - the inflection point where a product becomes a "must-have" for a well-defined market segment.

**Core Principle:** PMF is not a destination, it's a milestone that gives you permission to scale. Maintaining it requires continuous attention to customer needs and market evolution.

**Key Insight:** You can't manufacture PMF through marketing or sales tactics. PMF comes from deeply understanding a specific market segment and building something they desperately need. Scaling before PMF is the number one killer of startups.

**Historical Context:**
- Term coined by Marc Andreessen (2007)
- Operationalized by Sean Ellis with 40% rule (2010)
- Systematized by Rahul Vohra with Superhuman PMF Engine (2017)

## When to Use This Skill

**Auto-loaded by agents**:
- `product-strategist` - For PMF measurement, Sean Ellis survey, and retention analysis

**Use when you need**:
- Measuring product-market fit status
- Running Sean Ellis PMF surveys
- Analyzing retention curves
- Determining readiness to scale
- Diagnosing retention problems
- Planning PMF improvement strategies
- Deciding pre-PMF vs. post-PMF tactics
- Validating market expansion opportunities

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## Measuring Product-Market Fit

### The Sean Ellis Test (40% Rule)

The definitive method for measuring PMF through a single powerful question.

**The Question:**
> "How would you feel if you could no longer use [product]?"
> - a) Very disappointed
> - b) Somewhat disappointed
> - c) Not disappointed (it isn't really that useful)

**PMF Threshold:**
- **40%+ "Very disappointed" = PMF achieved**
- 25-40% = Close, keep iterating
- <25% = No PMF yet

**Why this works:**
- Measures must-have vs. nice-to-have
- Predictive of retention
- Correlates with organic growth
- Simple t