GA4 vs Universal Analytics - 7 key differences

During 2023, the deprecation of Universal Analytics (UA) got underway, finally making way for Google Analytics 4 (GA4). Despite GA4 being the default option for new Google Analytics properties created since October 14, 2020, marketers and web developers were in no rush to switch from UA to GA4 as their default reporting option. 

One likely reason for this is that Google Analytics 4 works very differently from its predecessor, and whilst it comes with many new valuable features, it has also suffered some backlash for perceived bugs and missing some adored features from UA. In this article, we will take a look at 7 key differences between the two platforms, and explain why it might be time to get excited about the new possibilities in GA4.

When will Universal Analytics be deprecated?

On March 16, 2022, Google announced in a blog post that Universal Analytics (UA) will stop processing hits on July 1st, 2023 for standard UA properties and October 1st 2023 (later extended to July 1st, 2024) for UA 360 properties. The relatively short time window between the announcement and the sunset date took many marketers by surprise and caused a mild panic amongst companies and website owners. Even though Google Analytics 4 had been out of beta since October 2020, adoption was still relatively low at the point of the announcement. This likely influenced Google’s decision to speed things up by introducing a sunset date for Universal Analytics sooner rather than later. 

More than a year might sound like ample time to add a new tracking script on a site, but it’s important to remember how critical Google Analytics is for most businesses when it comes to measuring performance. Before you start implementing Google Analytics 4, it’s crucial to understand how it is different from Universal Analytics. Check out our list of important differences below. 

7 key differences between GA4 and Universal Analytics

1. App tracking

One of the most anticipated functions of GA4 is the ability to track website and app data in the same property. GA4 leverages the same measurement model as Google Analytics Firebase (used for mobile apps) where all interactions are captured as events (more on that under point 2 below). This new unified data schema between a website and a mobile app means that it will be much easier to combine data across them. 

2. Hit types

Another significant difference between UA and GA4 is how interactions are captured. In UA, interactions were captured in many different hit types such as page views, transactions, and social interactions. In GA4 by contrast, every interaction is captured as an event. 

Events existed in UA as well; with an associated category, action, and label; but these classifications do not exist in GA4. Instead, GA4 works with event parameters that are additional pieces of information about the action (event) a user took. Some event parameters are sent automatically, such as page_title, and additional ones can be added (you can log up to 25 event parameters with each event).

Since the data models are fundamentally different, Google recommends that you do not simply copy over existing event logic from UA to GA4, but instead implement new logic that makes sense in this new context. 

3. Session calculations in GA4 vs universal analytics

Another difference between UA and GA4 that can become noticeable when you start comparing figures between the two systems is differing values for sessions. 

In UA, a session represents the period of time that a user is actively engaged with your site. After landing on your site, these are the things that ends a session in UA: 

• 30 minutes of inactivity (or your session timeout settings)
• The clock passing midnight (resulting in a new session)
• New campaign parameters are encountered (i.e. if you use UTM parameters for internal links on your website -- therefore, this is not recommended by Google). 

In GA4 by contrast, the session_start event generates a session ID with which all subsequent events during the session are associated. Similar to UA, a session ends after 30 minutes of inactivity (or your session timeout settings), but sessions can now carry over across midnight and are not affected by encountering new campaign parameters. If your site has a global audience, this can cause discrepancies in the Session figures you see for UA and GA4 respectively. 

If you want to learn more about how to accurately report on Sessions in GA4, check out this blog post. 

4. Exports to BigQuery are free with Google Analytics 4

With GA4, BigQuery exports are made available to all properties (for UA, this was limited to Analytics 360 properties). This means that you are able to send raw events to BigQuery, which can then be queried using SQL. The function itself does not cost anything as long as usage is within the sandbox limits for BigQuery. It’s worth noting that the sandbox environment does not support streaming data. 

5. Bounce rate and engagement rate

Some of the more notable omissions from GA4 are the metrics related to bounces. Instead, Google has chosen to take a more “positive” approach and report on figures for engagement rate. Simply put, engagement rate is a ratio metric presented as a percentage, and the formula is engaged sessions/sessions. 

What are engaged sessions you ask? These are sessions that lasted at least 10 seconds, had at least 1 conversion event, or had at least 2 page / screen views. 

So does bounce rate not exist in GA4? 

It does exist, but it is calculated a bit differently in GA4. In Google Analytics 4, bounce rate is the percentage of sessions that were not engaged sessions. In other words, bounce rate is the inverse of engagement rate, which is the number of engaged sessions divided by the total number of sessions in a specified time period. In UA, bounce rate was calculated as the percentage of website users that didn't view more than  page on your website.

6. Google Tag Manager is more important than ever

If you were using the more basic functionality of GA Universal, you could use it without Google Tag Manager. For instance, you could create destination page conversions in Google Analytics itself. 

 Example of an old-school goal destination page goal in Google Universal Analytics

Now, with GA4, this is no longer possible. All goals are event-based, so it is more important than ever to know your way around Google Tag Manager. Especially if you are working in digital marketing or e-commerce.

Understanding Tag Manager (or GTM) and being able to work with it, is also helpful for advanced data collection. For instance, you will need it to create custom events and custom dimensions.   

7. Account structure 

In GA Universal, the account structure contains 3 elements:

Account - Property - View

GA4 only contains two elements: account and property. This means that a Google Analytics 4 property does not contain any views.

Also, Google introduced a totally new concept in GA4: data streams. A data stream represents a flow from your website or app to Analytics. 

Whereas Universal collects data at the property level with a tracking ID, GA4 collects data at the stream level via a unique data stream ID. Each GA4 property can have up to 50 data streams and a limit of 30 app data streams.

Conclusion

Now that Google Analytics moves from a session-based data model to an event-based model, a lot changes. On July 11, 2022, Google announced new dimensions and metrics for GA4. Among those new metrics are bounce rate and conversion rate - 2 dimensions that marketing professionals had been waiting for. 

Now, it is up to us to start exploring and learning. Krista Seiden (ex Google employee, working on Google Analytics for years) said it like this on Twitter:

Want to keep updated on Google Analytics 4? Make sure to bookmark this page, where Google publishes all updates. And subscribe to our YouTube channel if you haven't already. We created a special GA4 playlist, where you can find all of our Google Analytics videos.