There could be several possible reasons why you’re seeing fewer page views in GA4 compared to Universal Analytics (UA). One possibility could be due to the different ways GA4 and UA track the pages of your website. While UA tracks every single page on your site, GA4 is more event-driven and might not automatically track certain pages. As a result, you might get a discrepancy in the page view data between the two. Additionally, if your GA4 setup is still new, it might not have received enough data yet to match the UA’s page views reports.
The use of adblockers or privacy extensions by your users could also cause such discrepancies. These tools often block tracking scripts but don’t treat all analytics software and versions the same and may consequently block one but not the other. Therefore, it’s also worth noting that the visitors’ behavior in terms of allowing or blocking cookies may play a role.
Lastly, make sure your GA4 configuration is properly set for accurate data collection. Incorrect setup like errors in tags implementation, event configurations, and others might also be a cause for these discrepancies.
In summary, discrepancies between GA4 and UA pageview data could be due to a number of reasons including differences in tracking methodology, data blocking by users, or even implementation errors. Investigating these areas might help you uncover why you’re seeing fewer matches with GA4.