Google Analytics 4 vs Universal Analytics: Data Model Differences
By Jeremy Neilson | November 21, 2023 | Google Analytics 4
Explore the differences between GA4 and UA. Make informed decisions for your website analytics. Discover more in our detailed guide!
Two analytics platforms: Why?
Google Analytics 4 (GA4) and Universal Analytics (UA) are two generations of Google’s major analytics platform released for tracking users and their journeys across websites, devices, and domains. While GA4 is the newer software, becoming the official focus of Google’s development as of October 2020, where does it stand when compared to UA? What are the differences, and what are the benefits of GA4 over UA for someone looking to install analytics and data tracking on their webpage?
To begin, let’s make sure we understand where these platforms come from, and why there are two to compare in the first place. Universal Analytics, sometimes known as GA3, was released by Google in 2013, with a special focus on being able to track users across multiple devices, using a session-based model and tracking users with unique User IDs. As the years progressed, Google provided continual support for UA. However, once October 2020 rolled around, Google no longer provided support for UA, instead focusing on active development for GA4, which was officially released at that time. GA4 features an entirely new data model, based around ‘events’. GA4 became the default option for new properties. As of July 1st, 2023, UA properties no longer process data.
While Google has made it fairly straightforward to transition to GA4, there are several differences between GA4 and UA features. Understanding the differences between these platforms benefits not only older users of UA but also allows for a great first look at GA4 for newcomers.
To give a brief overview, most features of UA are available in GA4, but most have slight changes that mostly streamline the user experience. GA4’s event-based model makes data collection in comparison to UA much more flexible and rich, allowing for many additional ways to display and report on data.
Data Collection
Below are most of the core elements of GA4, as well as a comparison of each feature with its UA counterpart (if it exists).
Events
Events in GA4 and UA are the most fundamental differences between the data models of these platforms.
Every action in GA4 is an event. Pageview, purchase, and form submission, all are reported as events, and all of them have parameters. Because parameters can differentiate between kinds of events, it is best practice in GA4 to reuse event names for similar actions. For example, using form_submit as the event for every form on your website, and differentiating between them in the parameters that are sent to GA4.
In UA, however, you create every event, and each one contains a Category, Action, and Label. UA’s default unit of data is a Hit, and events are additional actions that we can define and contextualize, that count as hits as well.
Parameters
This feature is what makes GA4 so powerful. Event parameters allow you to track additional contextual information alongside your events. store them in event parameters, and send them off to GA4. UA does not have this feature. That doesn’t mean UA can’t track that contextual information, it just depends on the action, and it is not nearly as straightforward as GA4’s parameters.
Users
Tracking the number of users in GA4 and UA can provide similar results, but there are differences because of default settings.
In GA4 reports, the reported number of users is calculated based on what Google calls “Active Users”, which are a handful of criteria that determine if a website visitor is included in the user count.
On the other hand, the default reported numbers in UA are based simply on the number of visitors that opened your web page, regardless of the length of stay, or the number of interactions they had.
Pageviews
Pageviews (or Views) in GA4 are counted as the number of pages seen by any user, mobile or web.
In UA, pageview calculations are the same. Still, the main difference is that mobile and web data are collected separately in different UA properties, but both kinds of data are collected in one property in GA4.
UA also offers data filters, a feature that excludes certain kinds of data from a report, like geographical location. GA4 does not offer filters like these.
Sessions
Sessions are tracked quite differently between UA and GA4, and GA4 will consistently track a lower number of sessions, though it is most likely a more accurate number than UA. There are several ways that UA can “accidentally” trigger a new session when it isn’t the case. Things like a session restarting after midnight or new UTM parameters causing a refresh. GA4 gets rid of most of these new session triggers, and now they’re only triggered by:
- Returning after a period of inactivity of longer than 30 minutes.
- Returning to the site after a session timeout.
GA4 creates a new session ID for each session on the site, and all events on the page are linked with that ID while it’s active.
How GA4 tracks activity during a session differs from UA as well. In UA, all user activity comes from interactive events, things you have installed on the website to be triggered by users. In contrast, even if you have no event triggers on your website, GA4 can track user activity, it is done automatically, and can be supplemented with additional events and given context via event parameters.
Conversions
Conversions in UA start as Goals and are tracked when a user completes said Goal. Each session will only count one conversion per Goal, though.
In GA4, conversion events act virtually identically to Goals in UA but have the added benefit of potentially being tracked multiple times per session. If a form is submitted twice in one session and there is a conversion event for it, GA4 will collect two conversions, while UA will collect only one.
Purchases
Collecting purchase information is a little more complicated in GA4 than in UA, though they have very similar approaches. UA’s Enhanced E-commerce Model tracks all the purchase information and supplies Javascript on the page that collects an Items array for the purchase event. All of that is automatic with purchase events.
In GA4, purchases are tracked via a purchase event, and an items array is a recommended inclusion, though that must be implemented on your own. GA4 purchases have several required parameters to ensure data is collected correctly:
- Currency: USD, CAD, etc.
- Value: The value in the selected currency of the purchase
- Transaction ID: A unique identifier for this transaction
- Items: A list of items included in the purchase
Takeaways
Though many of these differences may not seem too major, in practice they lead to an almost entirely different implementation strategy and user experience. GA4’s new tools and changes make using Google’s Analytics easier than ever, but with how varied and specific many said GA4’s features are, there are many ways to get the most out of the data your website collects.
Already have an existing GA4 property? Have it audited to ensure the data you’re collecting is meaningful and trustworthy.
For additional information and guides to help you on your journey with Google Analytics 4, whether it’s your first time with the platform, or you’re a Google Analytics veteran, check out our other blog posts on GA4.
