Analysis
Retention
Prerequisite: identify()
Retention is only computed for identified users. On anonymous traffic the id changes daily, so cross-day tracking is impossible — and the dashboard says so, with the reason, instead of showing an empty table.
Reading the matrix
- Cohort — the day a user was first seen.
- Day 0 — always 100% (that is the definition of the cohort).
- +N — share of that cohort who returned N days later.
- · — hasn't happened yet. An unmeasured day is never shown as 0%.
That last point looks like a detail and isn't: if a cohort started yesterday, writing 0 into the
"+3" cell presents something unmeasured as measured. We leave it blank.