What does landing page (not set) mean in GA4?

As in Universal Analytics, (not set) may appear in a number of reports in GA4.  (not set) essentially means Google hasn’t any data for a particular dimension or parameter. 

What are the causes?

The first thing to note is that it can take up to 48 hours for GA4 to fully process your data. If you’re seeing (not set) against a dimension for yesterday’s data, be patient and come back in a day or two and check again.

When it comes to landing pages, (not set) typically occurs for sessions where a “page_view” event wasn’t recorded.  Sessions time out after 30 minutes and so if someone visits your site and there’s then a period of inactivity the session may time out.

From Google’s documentation:

“In Analytics, a session initiates when a user either opens your app in the foreground or views a page or screen and no session is currently active (e.g. their previous session has timed out)”.

This means that if someone was viewing a page in another tab and then opens it again after the session has timed out, a new session_start and potentially a user_engagement event may fire without a page_view event.  This will lead to a new session without a landing page. 

You’ll see that when viewing data for (not set) in the landing pages report, the number of new users is typically very low backing up the fact that this is essentially existing users who are affected.

Finally for complex sites with advanced tracking do check your implementation. In cases where for example you’ve disabled enhanced measurement and have complex events firing it’s possible that there could be a tracking cause to the issue (check out our Google Analytics / Google Tag Manager audit service).

Have a question or looking for a Google Analytics agency to help with your setup?  Drop us an email at info@andersnalytics.com to find out more.