[GA4] Reporting identity

Learn how Google Analytics measures users across devices and platforms.

An individual customer often interacts with your business using different devices and platforms. For example, someone might browse your products on a Pixel tablet at breakfast, do more research using a browser on their work computer at lunch, then make a purchase on their iPhone after dinner. While each of these activities is a separate session, Google Analytics 4 can use four different methods to unify them into a single cross-device user journey:

  • User-ID
  • Google signals
  • Device ID
  • Modeling

Analytics creates a single user journey from all the data associated with the same identity. Because these identity spaces are used in all reports, they allow you to de-duplicate users and tell a more unified, holistic story about their relationships with your business.

Identity spaces

Collectively, the identifiers listed above are called identity spaces, and the identity space(s) used by your Analytics property is called its reporting identity.


If you create your own persistent IDs for signed-in users, you can use these IDs to measure user journeys across devices. To use this identity space, you must consistently assign IDs to your users and include the IDs along with the data you send to Analytics. User-ID is the most accurate identity space, because it uses data you collect to identify your users.

Learn how to implement User-ID.

Google signals

Google signals is data from users who are signed in to Google. When Google signals data is available, Analytics associates event data it collects from users with the Google accounts of signed-in users who have consented to sharing this information.

Learn how to activate Google signals.

Note: If you've activated Google signals for your property, you can turn off Include Google Signals in Reporting Identity on the Data Collection page under Data collection and modification in Admin. Turning off this option omits specific demographics and interest data from reports—specifically, data from signed-in, consented users. This option is useful if your property uses the Blended or Observed reporting identity, as it can help reduce the likelihood of data thresholding. Google Analytics will still collect Google signals data when this option is turned off so you can use the Google signals data in audiences and conversions, and share the data with linked Google Ads accounts for remarketing and bid optimization.


Analytics can also use device ID as an identity space. On websites, the device ID gets its value from the client ID. On apps, the device ID is the app-instance ID.


When users decline Analytics identifiers like cookies, behavioral data for those users is unavailable. Analytics fills this gap by using the data of similar users who do accept cookies from the same property to model the behavior of the users who decline cookies. Learn more

How Analytics determines the reporting identity

Analytics determines your reporting identity based on which identity spaces you choose to collect and which ones you make available via the following options.

Reporting identity options

  • Blended: By User-ID, Google signals, device ID, then modeling. Uses the user ID if it is collected. If no user ID is collected, then Analytics uses information from Google signals if that is available. If neither User-ID nor Google-signals information is available, then Analytics uses the device ID. If no identifier is available, Analytics uses modeling.
  • Observed: By User-ID, Google signals, then device ID. Uses the user ID if it is collected. If no user ID is collected, then Analytics uses information from Google signals if that is available. If neither User-ID nor Google-signals information is available, then Analytics uses the device ID.
  • Device based: Uses only the device ID and ignores all other IDs that are collected.

To get the full benefit of the first two options, you need to activate Google signals and collect user IDs. In addition, your property must have enough activity from signed-in users to adequately obfuscate their identity. When you activate Google signals, Analytics collects demographics and interests data when it is available. As a consequence, your reports are subject to data thresholds.

Note: The option you choose does not affect data collection or processing. You can switch between the options at any time without making any permanent impact on data.

Set the reporting identity for your property

  1. In Admin, under Data display, click Reporting identity.
  2. Select the reporting identity you want to use.
  3. Click Save.
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