Cross-cutting
Retention cohort
A retention cohort is a group of users who joined in the same time window (e.g. all signups in week 14), tracked over time to measure how many remain active. Cohort analysis surfaces whether retention is improving, plateauing, or degrading independent of acquisition growth.
Aggregate retention can deceive: a product with growing acquisition and flat absolute retention numbers can look healthy when each new cohort actually retains worse than the last. Cohort analysis splits the trend. The canonical view is a triangle table — rows are cohort weeks, columns are weeks-since-signup, cells show retention percentage. For B2B SaaS, weekly or monthly cohorts work; for consumer, daily.