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    Implement Google Analytics User ID in Google Tag Manager (GTM)

    Google Analytics 4 is the new-age analytics platform for helping marketers record hits, page views, sessions, and users.

    However, it’s important to note that ‘users’ may not necessarily represent unique individuals; they can include the same person accessing your site from different devices or browsers.

    Implementing the GA User ID can help you identify the number of users visiting your website from different devices and browsers.

    Google Analytics User ID enables you to unify the sessions of a user using different devices into one user, thus enabling accurate data generation.

    Sending a single User ID and related data from different devices and sessions to Google Analytics will create a unified and comprehensive view of the user’s interaction with your business.

    Specifically, GA4 offers four different methods to unify a single cross-device user journey:

    1. User ID

    2. Google Signals

    3. Device ID

    4. Modeling

    ‘Device’ basically means first-party cookies. If a visitor clears cookies or starts using a different device, that will be treated as a new user.

    Google Signals uses data from people using Google Accounts with ads personalization enabled.

    ‘Behavioral Modeling for Consent Mode’ is a GA4 feature or identity space for users who decline identifiers such as cookies. Analytics leverages observed data (the data of the users who have accepted cookies) to create modeled data for the users who denied tracking.

    However, the most accurate way of identifying visitors is the User ID. But it works well only if people can log in to your website.

    In the Admin panel, there is a section called Reporting Identity from where you can choose how to collect user data.

    How Can You Send a User ID to Google Analytics 4?

    To send a User ID to Google Analytics 4 (GA4), you can use different methods depending on your specific use case and platform. Any personally identifiable information (PII) cannot be sent to Google Analytics since it is against their terms of service. Therefore, ensure that you use a user identifier that is not considered PII.

    Here are some common methods used to send the User ID to GA4:

    1. Via gtag.js (JavaScript)

    To send a User ID to GA4, you can use the gtag.js library and include the following code on your website where the User ID is known:

    gtag(‘set’, {‘user_id’: ‘your_user_id’});

    2. Via Measurement Protocol

    You can use the Measurement Protocol to send data directly to GA4. Construct a Measurement Protocol request with the appropriate parameters, including the User ID. Ensure that you follow the Measurement Protocol documentation for GA4.

    3. Via the GA4 Configuration in Google Tag Manager

    If you use Google Tag Manager (GTM), you can configure a variable for User ID and use it in a GA4 tag. Set up a variable to capture the User ID dynamically, and then use that variable in the GA4 tag configuration.

    4. Using Firebase Analytics

    If your app is integrated with Firebase Analytics, you can use Firebase User ID as it seamlessly integrates with GA4. Firebase Analytics automatically sends certain user properties to GA4, including the User ID.

    5. Custom Events With User ID

    You can create custom events that include the User ID. For example, if you have a login event, include the User ID as a parameter when logging in. You can then track these events in GA4.

    Want to Implement GA4 User ID Using GTM? Request a Quote

    How to Insert User ID Variable and Implement Tracking for It?

    Implementing GA4 User ID using Google Tag Manager (GTM) involves configuring variables, triggers, and tags within GTM. Here are step-by-step instructions on how you can do it:

    Step 1: Create a Variable for User ID

    1. Open your Google Tag Manager account.

    2. Navigate to the container where you want to implement GA4 User ID.

    3. In the left sidebar, go to ‘Variables’.

    4. This is how you can create a new variable:

    a. Click on ‘New’.

    b. Choose the variable type based on how you collect the User ID (e.g., Data Layer Variable, JavaScript Variable, etc.).

    c. Configure the variable to capture the User ID value.

    Step 2: Set Up a Trigger

    1. In the left sidebar, go to ‘Triggers’.

    2. To create a new trigger, you can:

    a. Click on ‘New’.

    b. Choose the trigger type based on the event that indicates a user login or when the User ID is available.

    c. Configure the trigger conditions accordingly.

    Step 3: Configure the GA4 Tag

    1. In the left sidebar, go to ‘Tags’.

    2. To create a new tag, you need to click on ‘New’ and choose the tag configuration for GA4.

    3. Configure the GA4 tag by choosing ‘Google Analytics: GA4 Event’ as the tag type.

    4. To set up the GA4 configuration, you can:

    a. Choose the GA4 configuration tag you’ve already set up in GTM.

    b. Set the event name, such as “set_user_id” or another relevant event name.

    c. Add parameters to send the User ID. For example:

    ‘user_id’: {{User ID Variable}}

    d. Now, set the trigger to the one you created in Step 2 and save the tag.

    Step 4: Preview and Debug

    1. Click on ‘Submit’ to update the changes you’ve made.

    2. Before publishing to all users, use the ‘Preview’ mode in GTM to test the implementation. This allows you to view how your tags fire in real-time without affecting your live site.

    Step 5: Publish Changes

    After testing, if everything works as expected, click on ‘Submit’ again to publish the changes to all users. Monitor your GA4 reports to ensure that the User ID is being sent correctly.

    How Can You Use User ID Data?

    1. User Exploration – Go to Explore>User Explorer. You will find two types of App Instance ID values. One is the usual GA client ID and the other IDs are the ones you send as user_id to GA4.

    2. Segment Overlap – You can view how users interact with your website using different devices and how they overlap. Go to Explore>Segment Overlap and add two default segments—Tablet Traffic and Mobile Traffic.

    3. User ID Dimension Sign In – Implementing user_id tracking will unlock a new dimension called signed-in with User ID. When a visitor signs into your website, and you send user_id to GA4, the value of this dimension will be true for that user, otherwise it’d be false. You can make a comparison to ascertain the number of people who have signed in.

    Key Takeaway

    User ID tracking in Google Analytics 4 is, therefore, an improved feature as compared to the traditional Universal Analytics since a separate view isn’t needed. The data is applied to the entire property right after you send the user_id parameter with GA4 events.

    Should you like to know more, please write to us at [email protected] and we’ll take it from there.

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    1. How do I create or implement a Google Analytics 4 User ID?

    You can send a User ID to GA by adding the user_id parameter to the config command in the measurement code present on every page of your website.

    2. How do I integrate Google Analytics with GTM?

    In your new GA4 property, add a data stream for your website or mobile app. Create a GTM configuration tag and copy the measurement ID. Create a trigger to fire on all the pages, preview the changes done in GTM, and submit the container. To learn more about the integration, click here.

    3. What is the difference between Google Analytics ID and GTM ID?

    A series of letters and numbers that usually start with ‘G-’ form a Google Tag ID. You need a Google Tag ID to set up your Google Analytics 4 property using Google Tag Management. Google Tag Manager uses ‘containers’ to help you set up different groups of tags. Each container has a unique ID and the container ‘tag’ is the code for the container.

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