Track · 2:30 · Liner note
A Cohort Grows Up Together
Cohort analysis compares groups of users defined by a shared starting point, such as signup week, at the same age, so you can see whether newer groups behave better or worse than older ones.
Everyone who signed up in the same week shares a birthday, and that is all a cohort is: a group defined by a common starting point. A Cohort Grows Up Together follows each group as it ages, comparing week three of one cohort with week three of the next, never one calendar date with another.
The discipline lives in the grouping rule. Fix the starting event, fix what counts as active and label small cohorts as small. Then the chart answers a question averages cannot: whether newer groups are growing up better than older ones.