Resolve unassigned in GA4 User Acquisition report (Google Merchant Center)

The problem

In Google Analytics 4 (GA4), the User Acquisition report may show an unusually high amount of ‘unassigned’ traffic. This is a red flag 🚩 as this technically shouldn't be possible. The User Acquisition report in GA4 is designed to show where a user first came from. This is determined based on the very first page_view recorded for this user. With every page_view, there is normally always one of these three situations:

There is a referrer (the website the user came from)
There are UTM parameters present in the URL
If neither of the above are present, the traffic is automatically classified as ‘direct’

It is therefore technically impossible to have ‘unassigned’ users in this report, as one of these three situations should always apply.

The cause

This problem appears to be caused by specific auto-tagging settings within Google Merchant Center. This adds a parameter called ‘srsltid’ to URLs, which can interfere with normal traffic source tracking in GA4.

The ‘srsltid’ (Search Result Source Listing ID) parameter, added by Google Merchant Center to track the performance of product listings, can cause several problems in GA4:

The parameter can lead to distortion of analytics data as the same pages are counted multiple times as unique pages due to the different parameters or as organic traffic becomes fragmented in reporting.

GA4 has trouble correctly categorising traffic with this parameter, resulting in misallocation of organic search traffic and incorrect classification of free traffic from Google Merchant Centre listings.

This explains why traffic is flagged as ‘unassigned’. The parameter clashes with standard UTM parameters and GA4's ability to correctly recognise traffic sources. In addition, problems arise in the way GA4 processes this parameter in BigQuery exports, leading to missing or incorrect attribution of certain traffic sources.

The solution

To solve this problem, disable the auto-tagging feature in Google Merchant Center. To do this, follow these steps:

Log in to your Google Merchant Center account

Click on the cog icon (settings) in the top left corner

Navigate to ‘Tools and settings

Select ‘Automated enhancements’

Find the ‘Automatic item updates’ section

Set the switch for the autotagging feature to ‘Off’

After performing these steps, the problem of unassigned traffic in the User Acquisition report should disappear. It may take a few days before you see the change in your report, as GA4 needs time to collect new data.

Verification

You can verify that the solution is working by monitoring the User Acquisition report over the next few days. The percentage of ‘unassigned’ traffic should have disappeared and all this traffic should be correctly categorised as direct, organic, paid or referral traffic.

Updated on: 24/02/2025