How to fix unassigned traffic in GA4

Learn how to classify, track, and manage your web traffic effectively, ensuring your campaign traffic are never in the "Unassigned" category.

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Unassigned traffic in Google Analytics 4 (GA4) is a common headache for digital marketers.

It’s like trying to solve a puzzle with missing pieces: your data is incomplete, making it hard to measure the success of your marketing efforts.

This article covers the common causes of unassigned traffic in GA4 and tips to ensure your campaigns are accurately tracked and optimized.

What is unassigned traffic?

Unassigned traffic refers to web traffic that isn’t categorized under any of the traffic sources or mediums provided by Google Analytics 4 (GA4). 

Google Analytics 4 unassigned

Often, this arises when we use UTMs that reference traffic sources or mediums that GA4 doesn’t recognize. In such cases, Google labels this as Unassigned

While this is a frequent reason, there can be other factors causing this classification.

How does GA4 classify user acquisition and traffic?

The traffic source dimensions provide information about where the website or app traffic comes from. GA4 provides different dimensions to analyze it. Among the most used include:

Default channel groups


  • Identifies the origin of your traffic, like from a search engine such as Google, or another website.


  • Indicates through which method you acquired the website traffic, i.e., via organic, CPC, etc.

First user source / medium

  • Given at the user level, this indicates the source or medium responsible for the user’s initial session.

Session source / medium

  • Assigned at the session level, this represents what originated the session.
How does GA4 classify user acquisition and traffic

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What are the causes and how to prevent unassigned traffic in GA4?

Manual tagging based on source and medium

One of the main causes of unassigned traffic is the manual tagging of UTMs that do not follow Google’s recommendations.

UTM parameters enable you to manually tag URLs for emails, ads, and more. They can be easily added using Google’s Campaign URL Builder, providing insights into the origin of visits.

Google's Campaign URL Builder

The essential and most recommended tagging fields are: 

  • Source and medium, which will allow you to identify where the campaigns come from.
  • Campaign name, which allows you to assign a name to the campaign so you can analyze its results through the campaign dimension.

Below are common channels for manual traffic:

Common GA4 channels

If you don’t tag these fields per Google’s recommendations, GA4 will not be able to group them into its predefined categories, so the traffic will be labeled as Unassigned.

For instance, if we want to manually tag a newsletter URL, we will have to fill in the UTMs parameter fields using Google’s predefined ones:

*Newsletter is optional. If you choose to put this source, it is always recommended to stick with it. If not, we can set the name of the ESP used or look for how the source is tagged.

Sample URL campaign builder

When tracking links from another website, verify your source and medium tracking, then create a UTM with a campaign ID:

Referral traffic GA4

Referral traffic GA4 - campaign builder

For platforms like social networks or marketplaces, Google has a list of sources and categories to ensure accurate tagging and prevent unassigned traffic.

Other ways to prevent unassigned traffic

Since Universal Analytics ceased processing data beginning July 2023, GA4 has become the primary analytics tool from Google. 

This means the tool may still have bugs, discoveries and improvements. As of today, some other actions we can do to prevent unassigned traffic include:

Reporting identity

Google Analytics 4 uses methods like User ID, Google signals, Device ID, and Modeling for tracking user data across platforms. Selecting the right method can help prevent unassigned traffic. Device-based is the recommended one nowadays.

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Event configuration

Unassigned traffic can also stem from incorrectly configured events. Ensure your Google Tag Manager settings are spot-on. Events and parameters must also be tagged following Google’s guidelines.

Other causes of unassigned traffic include:

  • Events sent through regular tracking without session_start (h/t Antoine Eripre).
  • Incorrect session tracking due to short user visits, ad blockers, or connection and data collection errors.

Ad blockers and other devices

Devices or ad blockers that hinder Google’s data capturing can also cause misclassifications of traffic, Himani Kankaria has found. 

Simon Vreeman noted mobile apps as a potential source of channel assignment issues.

Use of audience triggers

As Himanshu Sharma highlighted the use of audience triggers in GA4 can greatly increase the volume of unassigned traffic.

If the event generated by the audience trigger isn’t tied to an existing session, perhaps because the session has ended or the criteria are met outside of the user’s current session, the source/medium might default to (not set) / (not set), which then appears as Unassigned in some GA4 reports.

Managing unassigned traffic in GA4

Addressing unassigned traffic in GA4 requires a combination of best practices, accurate tracking, and awareness of potential causes. 

Implement these tips to ensure your campaigns are accurately tracked and optimized, providing a more comprehensive view of your marketing performance.

Contributing authors are invited to create content for Search Engine Land and are chosen for their expertise and contribution to the search community. Our contributors work under the oversight of the editorial staff and contributions are checked for quality and relevance to our readers. The opinions they express are their own.

About the author

Gemma Fontané
Gemma Fontané is an SEO consultant, co-founder of Orvit Digital consultancy and founder of the international ecommerces & With her company, she leads strategies for B2B and Ecommerce companies to help them generate business. Gemma has knowledge and experience in international SEO as well as content and technical SEO. In the last year, as a public speaker, Gemma has spoken at conferences in different countries such as Friends of Search in Amsterdam, Search Y Paris 2022 in Paris or the International Search Summit in Barcelona and has collaborated with different industry blogs and seminars.

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