Method · 12 March 2026
Seven-day windows are not a vanity metric — until they are
Product rooms love Day-7 because it fits on a slide. That is not a reason to retire it. In App Retention Cohort Analytics, a seven-day window is a serious instrument when three conditions hold: the clock-start is written, the return event is named, and the comparison set is not silently edited for holidays.
The vanity version appears when those three conditions are skipped. Someone pastes a percentage from a vendor tile, the room nods, and a checkout experiment is paused. We see this often enough in Bangkok that the atelier now opens with a blunt exercise: reconstruct last month’s Day-7 from the raw export, not from the tile.
The stamp is the whole argument
First-open and first successful order are different clocks. A marketplace that reports Day-7 on first-open will look “healthier” during a campaign that drives curious opens and fewer completed baskets. That is not fraud. It is a mismatch between the question the room thinks it is asking and the stamp the tile actually uses.
Write the stamp in a sentence a non-analyst can read. If the sentence cannot be read aloud without a footnote, the window is not ready for a review.
Survival is not return
A user who still has the app installed is not the same as a user who opened a gated surface again. Day-7 survival and Day-7 return can move in opposite directions after a paywall change. Mixing them into one “retention” number is how subscription teams invent mysteries.
In Retention Windows Atelier we force two columns. Students complain. Then they stop mixing the story.
When we tell students to drop Day-7
If the product’s meaningful return cannot happen inside seven days — a lending app with a monthly cycle, for example — Day-7 becomes decorative. We still compute it once, to show the room why it misleads, and then we move the house conversation to Day-14 or Day-28. Dropping a window is allowed. Pretending it means something is not.
If your Day-7 is currently the only number leadership quotes, start with the Day-7 Survival Studio or write to the studio with the export you actually have.