Glossary · Business Analytics

Product-Market Fit

also: PMF

Definition

Product-market fit is the empirical condition where a cohort's retention curve flattens above zero — a group of users has found sufficient value to make the product a persistent part of their behavior. It is not a feeling; it is a quantifiable property of retention, NPS decomposition, and usage depth.

Andreessen's 'you'll know it when you feel it' definition is unhelpful for operators. The quantitative alternative: fit a shifted exponential R(t) = (R₀-R∞)·e^(-λt) + R∞ and test whether R∞ > 0. A flattening curve indicates PMF within that cohort. A composite score weighting retention (0.40), NPS decomposition (0.25), and usage depth (0.35) produces a single manageable metric.

Essays on this concept