Cohort Analysis.

Cohort analysis groups users who share a common characteristic — most often the time period when they first visited, signed up, or made a purchase — and tracks their subsequent behaviour over time. By comparing cohorts, analysts identify whether product changes, campaigns, or seasonality affect long-term retention and revenue.

Acquisition Cohorts

The most common cohort type groups users by acquisition date (day, week, or month of first session). Retention curves show the percentage of each cohort that returns in subsequent periods. A flat retention curve beyond week two indicates strong product-market fit; a steep early drop suggests onboarding or first-session experience problems.

Behavioural Cohorts

Behavioural cohorts group users by an action they performed — completing onboarding, making a first purchase, engaging with a specific feature — rather than acquisition date. These are more actionable for product teams because they reveal which early behaviours correlate with long-term retention.

Cohort Analysis in GA4

GA4's Exploration reports include a Cohort exploration template that shows user retention by week. BigQuery export enables more complex cohort analysis using SQL, including revenue cohorts, attribution-model cohorts, and multi-dimensional segmentation unavailable in the GA4 UI.