Daily Active Users DAU (also DAP "daily active people", "daily actives")
How many distinct people used the product on a given day.
The fork, why two teams get different numbers
Two disagreements hide in the word "active." First, the ACTION bar:
an "any-event" DAU (fired at least one tracked event, the default in
Amplitude/Mixpanel-style event stores) is much larger than a
"qualified-action" DAU (performed a defined value action) which growth
teams prefer, and both differ from a "session-open" DAU (opened the app,
the mobile-SDK default). Second, the IDENTITY unit: an anonymous
device/cookie DAU (analytics default) counts one human on phone + laptop
as two, while an authenticated-user DAU counts them as one but drops
every logged-out visitor. Marketing's dashboard and Product's dashboard
both say "DAU 41,000" off the same warehouse and mean different crowds.
The trap
Automated traffic and identity leakage both inflate it silently.
- The full trap, worked on a real export
- Every formula variant, spelled out
- The reconciliation anchor, what to tie it to and when to refuse
Reference: Product-analytics convention (no governing body) · MRC Invalid Traffic (IVT) Detection guidelines · IAB audience-measurement conventions