Field note · 9 June 2026
Reading retention without vanity metrics
Choose a return behaviour that represents received value—not simply another app open.
Retention is meaningful only when the return action represents value. An app open may be convenient to count, but it rarely explains whether a customer completed the job the product exists to help with.
Define the qualifying behaviour first. Then choose a time window that matches the natural rhythm of the service. Daily retention makes sense for some communication tools; monthly completed tasks may be more honest for travel or finance apps.
Compare cohorts using the same maturity window, note acquisition and product changes, and pair the curve with qualitative evidence. A declining line is a prompt for investigation, not a diagnosis by itself.
A useful next step
Write down the product decision this analysis should inform, the behaviour that represents value, and one plausible competing explanation. Those three lines are often enough to improve the next conversation.