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Reinstalls inflate installs in one tool

Google Ads and Firebase count reinstalls as installs while many MMPs do not. Learn how reinstalls inflate one tool's numbers and how to compare like with like.

Run the google installs troubleshooter →
SymptomOne tool, often Google Ads or Firebase, reports noticeably more installs than your MMP, especially for older apps.
Most likely causeGoogle Ads and Firebase count reinstalls as installs, while many MMPs only count a reinstall again after a re-attribution window.
First checkCheck whether your MMP counts reinstalls as new installs and what re-attribution window it uses.

Short answer: Google Ads counts Android reinstalls as install conversions and Firebase counts reinstalls as installs by default. Many MMPs only treat a reinstall as a new install after a re-attribution window. Older apps with many returning users show the biggest gap.

Why reinstalls are counted differently

Reinstall: an install of an app by a device or user that had installed and removed it before.

Google's developer documentation says Google Ads counts Android reinstalls by users who previously uninstalled as install conversions. Google's help centre says Firebase counts reinstalls as installs by default, while third parties often apply a re-attribution window.

How do I know reinstalls are the cause?

The gap grows with the size of your past user base and is larger on retargeting-style audiences. If the gap shrinks when you compare only new users, reinstalls are the cause.

Likely causes

  • Google Ads counts reinstalls. On Android, reinstalls are install conversions.
  • Firebase counts reinstalls. By default they are installs.
  • MMP re-attribution window. A reinstall inside the window is not a new install in many MMPs. The exact default is vendor-specific.
  • Install vs first open. Google Play conversions count downloads, so a reinstall that is never opened still counts in Google.

How to confirm it

  1. Check your MMP's reinstall and re-attribution settings.
  2. Compare Google or Firebase installs with MMP installs plus MMP reinstalls or re-attributions.
  3. Compare a brand-new app or market, where reinstalls are rare, with an established one.
  4. Check whether the Google conversion action is a Play install or your MMP's first_open.

How to fix it

  1. Compare like with like: add MMP reinstalls to MMP installs when comparing with Google or Firebase.
  2. Use your MMP's first_open conversion in Google Ads for bidding comparisons.
  3. Document your MMP's re-attribution window in your reporting notes.
  4. Report new installs and reinstalls as separate lines.
ToolCounts a reinstall as an install?
Google Ads (Android)Yes
FirebaseYes, by default
Typical MMPAfter a re-attribution window (vendor-specific)
AdAttributionKitMarks it as redownload

Apple's AdAttributionKit labels postbacks as download, redownload or re-engagement, so reinstalls are visible there too. The Play Install Referrer also resets on reinstall, according to Android's documentation.

See Google Ads shows more installs than the MMP and GA4 or Firebase installs differ from the MMP for related gaps, and run the Google installs troubleshooter.

Related

Related symptoms

AndroidAndroid installs from other stores never attributeThose installs have no Google Play Install Referrer, so the main Android matching signal is missing.→
FAQ

Common questions

Does Google Ads count reinstalls as installs?

Yes, on Android. Google's developer documentation says reinstalls by people who previously uninstalled count as install conversions.

Does Firebase count reinstalls?

Yes, by default. Google's help centre says third-party tools often apply a re-attribution window instead.

What is a re-attribution window?

It is the period after an install during which an MMP treats a reinstall as the same user rather than a new install. The default length varies by MMP.

Should reinstalls count as new installs?

It depends on what you pay for and measure. Many teams count them separately so that new-user growth and win-back campaigns are judged on their own terms.

What is mobile attribution?

Mobile attribution is the process of crediting each app install or in-app event to the ad, link or channel that drove it. A mobile measurement partner (MMP) does this across all your channels so each install is counted once.

Why do ad networks report more installs than my MMP?

Each network counts every install it touched within its own windows, including views, while an MMP gives each install to a single source. Adding the networks' numbers together therefore overstates real installs.