Strategy & economics
Cohort retention curve
Also known as: retention curve
A chart plotting the percentage of a cohort still active at each week or month after their start event — reveals the shape of retention decay: steep early drop-off, settling plateau, long-tail decline.
A cohort retention curve plots a single cohort's retention over time. X-axis: weeks or months since the cohort's start event (sign-up, first purchase, activation). Y-axis: percentage still active. Healthy curves show three phases: steep early drop-off (churn during onboarding, weeks 1-2), settling plateau (retained users stabilising into regular behaviour, weeks 4-12), and long-tail slow decline (natural erosion over months or years). Comparing curves across cohorts exposes whether retention is improving (each new cohort's 90-day retention beats the previous), degrading (product-market fit eroding), or flat. The shape of the curve matters more than any single percentage — a flat 60% retention curve is healthier than a steep 80% that drops to 30% by month 3.