Fix the “Unassigned” Traffic Issue in Google Analytics 4

With the transition from Universal Analytics to Google Analytics 4, there may be some issues you need to resolve. One of these issues is “unassigned” traffic. Dimensions appearing as “unassigned” / (not set) in reports negatively impact your ability to analyze and optimize.

We will discuss the causes of “unassigned” traffic in your GA4 reports and how to reduce it. This will enable you to better analyze your website’s visitor traffic performance.

What is “Unassigned” Traffic?

In GA4, “unassigned” traffic refers to web traffic that is not categorized under the default traffic sources or mediums provided by Google Analytics. “Unassigned” traffic appears in the default channel grouping in the Acquisition -> Traffic/User Acquisition reports.

Due to “unassigned” traffic, the true source of traffic and conversions cannot be determined, and therefore, the real performance of marketing channels cannot be seen. This prevents you from knowing which channels perform well, setting strategies, or understanding which adjustments need to be made.

How Does GA4 Classify User Traffic?

Google Analytics 4 uses several dimensions to classify and analyze traffic sources. Some of them are explained below:

• Default Channel Groups: Predefined groups by Google to categorize traffic sources into broader categories, such as Organic Search, Paid Search, Email, etc.
• Session Source/Medium: The source/medium that initiated a specific session, e.g., google/cpc, google/organic.
• First User Source/Medium: The source/medium responsible for a user’s first session, e.g., (direct)/(none), facebook/cpc.
• Source: Defines the origin of traffic, such as google, facebook, (direct).
• Medium: Indicates how the traffic was acquired, e.g., organic search, CPC, email, referral.

There are currently 18 default channel groups:

• Affiliates
• Audio
• Cross-network
• Direct
• Display
• Email
• Mobile Push Notifications
• Organic Search
• Organic Shopping
• Organic Social
• Organic Video
• Paid Other
• Paid Search
• Paid Shopping
• Paid Social
• Paid Video
• Referral
• SMS

Causes of “Unassigned” Traffic

There are many factors that cause “unassigned” traffic in GA4:

1. Incorrect UTM Parameters: One of the most common reasons is using incorrect or non-standard UTM parameters. For example, using utm_medium=mail instead of utm_medium=email for an email campaign can result in “unassigned” traffic because GA4 does not recognize the custom parameter. You can refer to Google’s documentation to ensure correct tagging.
2. Google Tag Issues: Incorrectly set up tracking codes can prevent GA4 from correctly associating traffic sources.
3. Ad Blockers: Many users use ad blockers, which can prevent GA4 from collecting data accurately.
4. Cross-domain Tracking Issues: Incorrectly configured cross-domain tracking can cause UTM parameters to be lost during redirects, leading to “unassigned” traffic.
5. Missing session_start Events: The absence of session_start events can cause GA4 to incorrectly attribute traffic.
6. Misuse of Measurement Protocol: Incorrect use of GA4’s Measurement Protocol, such as missing client_id or session_id, can lead to “unassigned” traffic.
7. Google Ads Auto-tagging: Not properly linking Google Ads with GA4 or disabling auto-tagging can cause traffic from Google Ads to appear as “unassigned.”
8. Bugs: Directly related to Google updates or other actions could also cause issues. In some cases, waiting might be the only solution.

How to Fix “Unassigned” Traffic?

To reduce “unassigned” traffic in GA4, the following options should be checked:

1. Correct UTM Tagging: Consistently use the correct UTM parameters. For example, always use utm_medium=email for email campaigns. Use Google’s Campaign URL Builder to standardize your UTM tags.
2. Correct Google Tag Setup: Ensure the GA4 tracking code is correctly set up on all pages. Ensure the snippet code is placed immediately before the </head> tag. Tools like Tag Assistant or GA4 DebugView can help with this verification. If the GA4 event tag fires before the Google tag, this can also increase the number of “unassigned” source/medium.
3. Auto-tagging: Enable auto-tagging for platforms like Google Ads to prevent manual tagging errors.
4. Cross-domain Tracking: Properly configure cross-domain tracking to ensure UTM parameters are preserved across domains.
5. session_start Event Configuration: Ensure the session_start event is correctly implemented to prevent incorrect attribution of traffic.
6. Measurement Protocol Implementation: If using Measurement Protocol, ensure you include client_id and session_id in your data.
7. Reporting Identity: GA4 uses methods like User ID, Google signals, Device ID, and Modeling to track user data across platforms. Ensure your settings are configured correctly. If settings are done via Google Tag Manager, check your configurations. Events and parameters must also follow Google’s guidelines.

Conclusion

“Unassigned” traffic in GA4 is a manageable problem with proper and consistent practices. By understanding its causes and applying best practices in tracking and tagging, you can significantly reduce its impact and gain more accurate insights into your marketing performance.