Unique users
A unique user is a device counted only once, no matter how many sessions or actions happen on it. It's the basis for many marketing metrics in AdShift, including:
- Installs — unique devices that installed the app.
- Event unique users — unique devices that performed a given in-app event.
- Active users (DAU / WAU / MAU) — unique devices that opened the app in the period.
How AdShift counts a unique user
Unique users are counted by a stable device identifier that the AdShift SDK assigns on first launch — the same identity used for active users (DAU / WAU / MAU). Because that identifier stays the same across all of a device's sessions and events, the device is counted once regardless of how active it is.
- For iOS traffic measured through SKAdNetwork (SKAN), where Apple doesn't expose device-level data, unique counts come from Apple's aggregated SKAN reporting instead of a device identifier.
- Unique-user counts are statistical estimates (about a 1–2% margin), so they won't reconcile to an exact headcount. Event counts and session counts themselves are exact.
Unique users and view types
Unique users can be viewed as Unified, User acquisition (UA), or Retargeting:
- User acquisition — devices counted against their UA (install) media source.
- Retargeting — devices counted against their re-engagement / re-attribution media source.
- Unified — every device counted once, regardless of how many campaigns touched it.
Important: the Unified view de-duplicates the device. A device that installed via UA and later came back via retargeting is one unique user in Unified — it appears in the UA view (for its install) and in the Retargeting view (for its re-engagement), but Unified is not the sum of UA + Retargeting. The two views overlap on the same device by design (the same principle as revenue).
Use cases
Install and reinstall
The install and the reinstall are the same device, so only 1 unique user is counted. Events from the reinstall are attributed to the same user as the first install.
If a reinstall can't be linked to the first install — for example, the device no longer reports a usable identifier — it's treated as unattributed organic, and its later events aren't included in the unique-user count.
Install and re-attribution
The re-attribution happens on the same device as the original install, but it's recorded as a retargeting conversion.
| View | Unique users | What it represents |
|---|---|---|
| User acquisition | 1 | the original install |
| Retargeting | 1 | the re-attribution |
| Unified | 1 | the device, counted once |
The re-attribution is still counted as its own retargeting install in the Retargeting view — you don't lose it. What doesn't happen is the device being counted as a second unique user in the Unified total.
Install and re-engagement
Same as re-attribution, except the re-engagement is recorded against an app open rather than a new install. The original install shows in the UA view (1), the re-engagement shows in the Retargeting view (1), and the device is counted once in Unified (1).
Unattributed in-app events
When an in-app event can't be linked to an attributed install — for example, after a reinstall that doesn't report a usable identifier — it isn't included in the unique-user count at all. There can be other reasons an event is organic-unattributed; in those cases too, the event doesn't add to the unique-user count.
Limitations and things to know
- Active users (DAU / WAU / MAU) are always Unified. The view-type toggle splits acquisition and revenue metrics, but active users are reported as one app-wide figure (each device once).
- Reinstall recognition depends on identity. A device is recognized as the same unique user only while it keeps its stable identifier. If a new identifier is assigned (which can happen on some platforms or under certain privacy settings), the reinstall may count as a new unique user.
- Unique-user figures are estimates (~1–2%); don't expect them to reconcile to an exact unit.
- SKAN data has no device-level identity. For SKAN-measured iOS traffic, unique counts come from Apple's aggregated reporting, separate from device-based counts.
Related
- Attribution model — how installs and in-app events are attributed.
- Resolve retargeting double attribution — how in-app events are credited to UA and retargeting.
- Measure sessions — how sessions and active users are counted.