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On 1 July 2023 Universal Analytics (UA) will stop recording traffic.

In its place, Google has launched Google Analytics 4 (GA4). This next-generation measurement solution uses modern, privacy-safe tracking methods and, thanks to machine learning, less data will be lost as a result of cookie developments and non-consenting users.

GA4 can track more and better-quality data, allowing for a more accurate insight into website traffic and user activity. Amongst other new exciting features, it also allows for measurement across multiple devices and platforms, which will help offer valuable insight into how your users convert.


Why do I need to move to GA4?

After July 1st 2023, UA will stop recording and collecting traffic data. If you rely on Google for website analytics, you will need to make this switch so that you can continue measuring website performance.

Around 50% of users refuse the use of cookies, meaning that UA could currently be heavily under reporting these users, GA4 uses machine learning to fill in the gaps from data not being collected by cookies and needs time to train on your site data to model these users.


How is GA4 different?

Google describe GA4 as a future-focused and privacy-first platform as it relies less on cookies to track and record certain events and platforms, helping to future-proof your data, and passes privacy control settings to the admin user

GA4 also allows for measurement across multiple devices and platforms, enabling analysts to more accurately track a user who starts on a mobile device and converts on a desktop, for example. Having a more informed view of the customer journey also allows for better optimisation.

Unlike UA, GA4 combines data from apps and websites into the same platform, meaning all the data is in one place, making analysis more streamlined.


Why is GA4 different?

GA4 uses completely different building blocks to UA and it measures data differently.

  • UA is session based, built upon interactions that take place during a session. The UA hierarchy was made up of a combination hits/views, sessions and users.
  • GA4 is event based and any interaction with the website can be captured as an event, making it much more customisable and scaleable.

Instead of seeing GA4 and UA as two rulers with different scale increments, it is more appropriate to see one is a tape measure and the other is a set of weighing scales. They both report on your website analytics but achieve it in a completely different way.

As well as how data goes into GA4, how it is processed into reports is different too. Because of advances in non-cookie based measurement techniques, GA4 allows you to change between ‘Reporting Identities’ and apply this change dynamically to your data. This setting will change how your users and sessions are calculated in your reports.

From our testing, ‘Device based’ is the closest reporting identity to how UA calculates data but this is not a long term solution for interpreting your data. To get the most out of GA4, you should enable Google Signals and use ‘Observed’ or ‘Blended’ data, where possible once your account has accumulated enough data.


Why does my data look different?

The data will never match up perfectly. Although the metric might be called the same, it’s the building blocks behind it that are fundamentally different. Using ‘New Users’ as an example:

  • UA – Number of users who interacted with your site for the first time.
  • GA4 – number of users who interacted with your site or launched your app for the first time. Measured by the number of unique user IDs that logged the first_open or first_visit event.

What to expect when comparing metrics between GA4 and UA

In addition to this, here are a few additional reasons why the metrics don’t match up:

  • With increased users refusing cookies, it’s possible that your UA has been underreporting for some time.
  • GA4 defaults to data driven attribution, whilst UA is last click.
  • GA4 uses modelled data to fill in gaps.
  • GA4’s cross device measurement could result in fewer unique users.


What will happen to my reporting?

For our clients, we will be keeping the same reports but replacing UA metrics with the GA4 equivalent. For a few months, where the data is available, we will report on key metrics side by side to demonstrate how different the reporting might be and to manage expectations.

The metrics will not match and historical comparisons will be impacted due to not being able to import UA data.


What will happen to my UA data?

After July 1, 2023, you will still be able to access your UA property for at least six months. We are advising clients to use this period to export their historical data.

Google is yet to announce a final, future date for when UA properties will not long be available or accessible but it’s worth keeping in mind that, after this data, you will no longer be able to see your UA data either through the web platform or through the API.


How have goals and data changed?

‘Goals’ are now ‘Conversions’ and it is possible to track up to 30 (10 more than UA’s 20).

At Fountain, we’ve used the migration as an opportunity to audit existing measurement to identify potential opportunities and finesse current tracking. In most cases we have reproduced UA goals in GA4 using the new data models.

GA4 is a massive measurement shake-up, and everything is going to be different. The discrepancies between both data sets will vary based on a myriad of factors and it’s very important not to get bogged down in focussing on these differences.

As we acclimatise to the new measurement, Fountain will be keeping an eye on other sources like Google Ads, Search Console and CRM data to ensure continuity. GA4 is here to stay and it’s meant to be different. It’s time to get comfortable with new metrics and different numbers.


This is an update to a previous article published in April 2022.