#product-market-fit

Measure and validate product-market fit. Indicators: 1. Sean Ellis test (% users 'very disappointed' if product disappeared >40%). 2. Retention cohorts (flattening curve after initial drop). 3. Organic growth rate (word-of-mouth, low CAC). 4. NPS score (>50 is excellent). 5. Sales cycle length (decreasing over time). 6. Customer feedback themes (solving real pain). Conduct surveys and analyze usage data. If PMF not achieved, pivot or iterate. Document assumptions and validate continuously.

Achieve and measure PMF. Indicators: 1. Sean Ellis test ('how disappointed if product went away?' >40% 'very'). 2. Organic growth and word-of-mouth. 3. High retention rates. 4. Users getting core value quickly. 5. Revenue growth acceleration. 6. Qualitative: strong customer enthusiasm. Before PMF: talk to users constantly, iterate quickly. After PMF: scale efficiently. Don't scale prematurely. PMF is not permanent - can lose it.

Measure and achieve product-market fit using multiple signals. PMF indicators: 1. Sean Ellis test: >40% of users would be 'very disappointed' if they couldn't use product anymore. 2. Retention curves: cohorts flatten to horizontal line (not declining). 3. Organic growth: word-of-mouth driving 30%+ of new signups. 4. Usage intensity: users engaging multiple times per week. 5. Net Promoter Score >50 and growing. Measurement cadence: survey users quarterly, analyze retention monthly, track referrals weekly. Early PMF signs: customers pulling product from you, usage growing organically, positive unit economics emerging. Pre-PMF: focus on retention over growth. Post-PMF: optimize growth engines. Tools: Amplitude for retention, Delighted for NPS, internal surveys for disappointment test. Document learnings about ICP (ideal customer profile) refinement.