Cohort triangle builder
Tallyo, a budgeting app, shipped a new onboarding flow in April. Sam wants to know if new users stay longer. Here the retention triangle is built from the lesson's 298 users and 716 raw events, right in your browser.
1. One cohort, user by user
One row per user, one column per month number. A filled square means the user had at least one event that month; the digit is how many events. Dashed squares are months after the data ends (30 June 2026).
2. The triangle
3. Spot the mistake
A colleague's slide shows this triangle. One cell was computed by counting events instead of distinct users. Click the cell you think is wrong.