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GA4 vs Universal Analytics: What’s The Difference?

June 2nd 2023


Chances are, you’ve probably heard of Google Analytics 4 (GA4) by now. It’s the new and improved version of Universal Analytics (UA), which is set to take over next month. But what’s new, what’s improved, and what does any of it mean? Here’s a quick rundown of almost everything you need to know about GA4.

Different measurement model.

UA measures ‘hits’, which is a particular type of interaction. For example, a page view or an email click would both be hits, albeit different types. GA4, on the other hand, doesn’t distinguish between different types of hits. Instead, they’re all called ‘events’.

Event-based data.

So as you now know, GA4 uses event-based data – unlike UA, which uses session-based data. Therein lies our first can of worms – what’s an event from a session? Bear with us.

A session à la UA is a group of interactions that someone has with a website during a single visit. Imagine they click through a few pages, watch a demo video and then purchase your product – join them all together using cookies and you’ve got yourself a session.

Events, on the other hand, don’t rely on cookie tracking to capture user interactions within a given time period. Instead, GA4’s event-based model uses machine learning to fill in the gaps and allows for cross-device and cross-platform monitoring.

So, long story short: sessions are out, events are in, which means enhanced monitoring capabilities without the need for cookies.

No more bounce rate.

Where UA measures ‘bounce rate’, GA4 instead measures ‘engagement rate’, and there’s a subtle difference between the two. Let’s start with bounce, which is defined as a single-page session on a website. If someone spends several minutes on a single page and then clicks away without visiting another page or triggering any other events, that’s classed as a bounce – at least by UA. GA4, on the other hand, has slightly higher thresholds. A session is only engaged if it lasts more than 10 seconds, or the user triggered a conversion event or moved to another page. If 10 seconds doesn’t feel enough, you can increase this time up to 60 seconds in your settings.

If you ask us, engagement rate is a very welcome addition. It gives you a far better handle on user engagement, especially when it comes to long landing pages or Single-Page Application (SPA) websites. But if you do find yourself missing the good old bounce rate, this will simply be the percentage of sessions that were not engaged sessions.

No more Category, Action, Label.

In UA, events are structured with a hierarchy of Category, Action and Label. These values are predefined, with each event needing to be assigned these attributes. In GA4, events are simply given names and any additional information is sent as parameters within those events. Think of it as a more flexible, configurable system.

For example, a video play event in UA might look like this:

Category: Videos

Action: Play

Label: Fall Campaign

The same event in GA4 might be named ‘video_play’, with parameters like this:

video_name: Fall Campaign

video_duration: 120

A new feature within GA4 events is that you can add as many parameters as you like, giving you even more meaningful insights into user behaviour.

GA4 vs. UA Metrics.

Here’s an overview of the new GA4 metrics and their UA equivalents.

UA Metric GA4 Metric
Bounce Rate  Engagement Rate (i.e. opposite of Bounce Rate)
Ave. Session Duration Ave. Engagement Time per Session
Ave. Time on the Page Ave. Engagement Time per User
Pages / Visit Events per Session 
Page Views  Views (i.e. the same metric, but renamed)
Goals Conversions


Introducing enhanced capabilities, richer data and predictive analytics, GA4 is certainly a step up from UA. One of the main differences between them is that events have taken over from sessions, with the added bonus of cookieless monitoring across devices and platforms. The key date to remember is 1st July – that’s when you’ll have to switch over from UA to GA4 (unless you opt out). We’d recommend starting to get familiar with GA4’s new features now so you’re ready for the switchover when it comes.

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