Research Shows a 23% Divergence Between UA and GA4

TLDR;

To compare and contrast the way Universal Analytics (UA) and its newest version, Google Analytics 4 (GA4) collect data, we sampled multiple clients with both accounts over the month of October 2022. When comparing the UA and GA4 data side by side, we observed variations that average a 23% difference in the numbers between the platforms. We will be expanding further on the discrepancies found during this study.

Why are divergences in Universal Analytics and Google Analytics 4 data important?

The upcoming switch to Google Analytics 4 is approaching. After July 1st, 2023 the Universal Analytics platform will be going away forever and leaving behind Google Analytics 4 to take over all web analytics for website traffic online. It is important to better understand and depict the way data is measured across the two platforms for utmost success when setting website traffic goals.

Comparing Data from Universal Analytics with Data from Google Analytics 4

Throughout the month of October, we sampled over 30 clients that had active Universal Analytics and Google Analytics 4 accounts on their websites. We measured the data from both accounts focusing on three main metrics: User data, Session data, and Conversions data. Considering that these metrics do not translate exactly from UA over to GA4, the numbers we used are the closest equivalents of each other for the most accurate comparison. 

Although changes are expected when using a new platform, the differences need to be acknowledged. We calculated that there was an average of 5.3% difference in User data, a 3.2% difference in the Session data, and an astounding 65% difference in Goals data. Overall a 23% percent difference in all data when aggregated. 

What are the differences in User data in UA and GA4?

One of the main differences between User data in UA and GA4 is the primary metrics used. In UA, the primary metric is Total Users. This means that all users that visit the site are counted equally. In GA4, the primary metric used is Active Users. Only users that have an engaged session with the website are counted. An active user is described as someone who has been on any page longer than 10 seconds, completed a conversion event, or viewed two pages. 

Another difference is that Google states that GA4 is able to differentiate users across different platforms and devices. We are speculating this means that someone using their laptop and phone simultaneously would only be counted once in GA4 as opposed to twice in UA. This may have resulted in an average of 5.2% lower User data. However, even though traffic may appear lower in GA4, it is more certain that your users are not being duplicated and are engaging with your content.

How are Sessions data in UA and GA4 divergent?

The difference between Sessions data in UA and GA4 was smaller than the User data percentage with an average of a 3.2% change. This is most likely due to the fact that the definition of a session in UA versus in GA4 is fairly similar. Therefore, the numbers did not have a very noticeable change.

The big adjustment is that GA4 will be moving from grouping data into sessions to grouping it into events. An event consists of any interaction the user has with the website. This is completely customizable but some events that are automatically collected according to Zac Duncan from Root and Branch Group are:

• session_start
• first_visit
• user_engagement

Why are conversions measured so differently in UA and GA4?

The biggest difference in our data happened when measuring conversions with an average percentage change of 65%. This correlates to what we mentioned above. Sessions are now events and events can equal conversions. We noticed that GA4 had higher conversion data than UA due to GA4 counting every event that occurred as a conversion. For example, GA4 was counting every single form fill or phone click despite the fact that it may have been clicked twice (or multiple times) by a user. We are able to see the Total Users next to conversions with a more realistic number, however, one must be very careful and remember it may be counting multiple conversions for one user.

UA

GA4 

The Conclusion 

All in all, this study was able to show how Google Analytics 4 will be measuring data in comparison to Universal Analytics. This is a big change that will require some getting used to. The biggest takeaway from this is that once you start collecting data with GA4, ensure the data you want to track is set up properly on the platform. This may be difficult to adjust to since it is a bit overwhelming to see all the ways GA4 lets you customize your data. That being said, once adjusted, you will be able to track all analytics data perfectly to your business needs.