As a marketer or website owner, it’s crucial to have a complete view of your customer journey across different devices and touchpoints. And even if this is getting harder and harder to do, there are several methods that Google Analytics 4 uses to accomplish this, each with its own strengths and weaknesses. In this article, we’ll take a closer look at these methods and how they work.
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Google Analytics uses four different “identity spaces” to track users across devices and platforms. These are user ID, Google signals, device ID, and modeling. Let’s take a closer look at each one.
- User ID: User ID is a unique identifier that you assign to your users. You can send this identifier to Google Analytics when visitors log in to your website or app. The key advantage of User ID is that it remains the same across different devices and platforms. So if a user logs in on their laptop, and then later on their mobile device, they will still have the same user ID. This allows you to track their behavior more accurately.
- Google Signals: Google Signals is data from users who are signed into their Google accounts. If a user is using Google Chrome and has signed in to their Google account, and they have opted in to share this information, Google Signals will use this information to attribute different visits from different devices under the same user (as long as they were logged in under the same Google account). To use Google Signals, you need to activate it in your Google Analytics property.
- Device ID: Device ID is a unique identifier for each device that accesses your website or app. On websites, Device ID is stored in the form of a cookie known as the Client ID. In apps, the Device ID is the App instance ID. The Device ID is less reliable than User ID, as users can clear their cookies or use different devices (in which case the same person will have assigned multiple GA4 identifiers = cookies).
- Modeling: Modeling is a method that uses anonymized data to create models of user behavior. This method is only available if you have implemented Google Consent Mode, which allows you to collect data from users who have not opted in to analytics cookies. The anonymized data is used to create models that can help with identifying users.
Once you have collected data using these identity spaces, Google Analytics uses three different options for reporting identity: device-based, observed, and blended.
- Device-based: This option uses Device ID as the identifier.
- Observed: This option uses User ID if available, followed by Google Signals if enabled, and then Device ID.
- Blended: This option uses a combination of User ID, Google Signals, Device ID, and Modeled data if nothing else is available.
It’s important to note that if you have enabled Google Signals and are using observed or blended reporting identity, you may experience data thresholding in your Google Analytics reports.
Changing Reporting Indentity
Finally, it’s worth noting that the reporting identity you choose doesn’t affect how the data is processed in your Google Analytics property. You can change the reporting identity, save it, and the data will be recalculated retroactively. This allows you to experiment with different reporting identities and see how they affect your metrics.