How To Migrate To Google Analytics 4 Without Losing Data
Summarise this blog
Table of Contents
Key Takeaways
- Google Analytics 4 is Google’s event-based analytics platform, launched in October 2020, and the only version still running: Universal Analytics stopped processing data on 1 July 2023 and was deleted in July 2024.
- GA4 was built for the privacy era, collecting cross-device, cross-platform data without identifying individuals and modelling the gaps left by users who decline cookies.
- Moving from Universal Analytics was never only a new tracking code: events, parameters, custom dimensions, filters, goals and attribution all had to be rebuilt.
- Seven settings are commonly left unfinished: event migration, parameters registered as custom dimensions, data retention raised from 2 to 14 months, internal traffic excluded, Google products linked, key events marked, and attribution set for Google Ads.
- Each one can be fixed in Google Tag Manager or the GA4 admin panel in minutes.
Setting up Google Analytics 4 can be done several ways, but for some people it is complicated and mistakes are common. This GA4 migration guide covers what to know about moving Universal Analytics (GA3) events to GA4 events, so the move to Google Analytics 4 is complete rather than half done.
First, a quick refresher on what Google Analytics 4 is.
What Is Google Analytics 4?
Google Analytics (GA) is an essential tool for every kind of brand, letting marketers analyse their own website in depth. Before Google Analytics 4, the main version in use was Universal Analytics, or UA. In October 2020, Google released Google Analytics 4 (previously called the App and Web property), a major change, because this version is built around micro-moments and aligns with the data privacy of the people being measured.
Why Move To Google Analytics 4?
Cross-Device Analysis
Google Analytics 4 gives a deep understanding of user behaviour by collecting usage data across devices, website and app alike, without identifying individuals, so users keep their privacy.
A Clearer Customer Journey
Google Analytics 4 lets you see the same user across the website and the app, where before they appeared as two people, for a more complete view of the customer journey. Users who once consented to cookies on a site or app can also ask for their cookie ID to be deleted.
Easier Marketing Activation
Google Analytics 4 opens up conversion insight so advertising reaches users across platforms more effectively, with data flowing from GA4 straight into BigQuery for further use, such as building audiences or running personalised ads.
More Accurate Predictive Analytics
Google Analytics 4’s machine learning closes the gaps in conversion data through consent mode modelling, filling in for users who decline cookies, and surfaces insights that make the analysis more effective and more accurate.
How To Migrate To Google Analytics 4, The 7 Steps People Miss
As mentioned, Google Analytics 4 can be set up several ways, but the popular route is through Google Tag Manager, because it is simple. Even so, several steps are often skipped, which leaves the setup incomplete.
Moving from Universal Analytics to GA4 changed more than the tracking ID. It changed the whole structure, from how events are tracked to every setting that was configured before, which is why some settings never made it across. Here are the steps most often missed, and how to fix them.
Bring Universal Analytics Events Into Google Analytics 4
Google Analytics 4 runs on a base unit called the “event”, which measures precisely whether a visitor took a specific action. Moving from Universal Analytics, or GA3, to GA4 was never only a tracking code change: the events had to come too. The move from GA3 events to GA4 events is simpler than it sounds. Use Google Tag Manager to manage the events, then change the trigger and send it to GA4.
For example, suppose you set an event called “Play VDO” to show whether a user played your video. Under Universal Analytics you set an event category of Video and an event action of Play, which told you which video the event belonged to.
Under Google Analytics 4 the whole thing is rebuilt. The event name stays “Play VDO”, but a parameter such as video_name now records which video was played.
Register Parameters As Custom Dimensions
After the events are moved, you may go back into GA4 and find the parameter missing, even though it showed during debugging.
The cause is that when the event is created, each parameter also has to be registered as a custom dimension in GA4. Without that, the system shows the value only in real-time reports. The limit is 50 event-scoped custom dimensions per standard property, so some events may need to share a parameter name.
Change Data Retention From 2 Months To 14 Months
Before relying on Google Analytics 4 fully, change the data retention setting. It governs how far back the Explorations reports can reach. Left at the default of 2 months, any custom report beyond the standard set only draws on the latest 2 months. Extending it to 14 months lets Explorations run further back.
Exclude Internal Traffic And Spam
Universal Analytics lets you split views into Master, Filtered and Unfiltered to screen out internal visits and spam. GA4 has no views, so people coming from Universal Analytics often miss this step. The fix is to define internal traffic (your own team’s visits to the site) and activate the data filter that excludes it, and to filter out unwanted referrals.
Link GA4 To Other Google Products
GA4 offers many functions, including links to other Google platforms, and this version links to more of them: Google Ads, Google Play, Google Search Console and Google BigQuery among them, so data from those platforms can be viewed inside GA4 directly.
Mark Events As Key Events
In Universal Analytics we were taught to set goals, so the site’s objectives were defined and we could check precisely whether visitors did what we wanted. The most popular goal type was “Destination”, counting users who reached a “thank you” page. GA4 works differently: because everything is an event, the old goal becomes an event sent through Google Tag Manager and marked as a key event, the event that represents your objective. Google renamed GA4 conversions “key events” in March 2024 to separate them from Google Ads conversions.
Change The Attribution Model After Importing Key Events Into Google Ads
GA4’s default is data-driven attribution, where Google’s machine learning assigns credit differently per user. If you import key events into Google Ads as conversions, remember to review the attribution setting, including the last click option, so that the values show in Google Ads and can be measured properly.
Summary
That is what to know about moving GA3 events to GA4 events, and every brand should have the setup complete, because data cannot be collected retrospectively. GA4 is the right tool for modern marketing, because it puts customer behaviour first through its event-based model, which gives a more detailed understanding of the customer journey and more real-time data to feed the next marketing plan straight away. At the same time, GA4 protects user privacy by letting users decline consent for data collection and cookies.
If you would like this tool installed properly to understand your customers better, or a GA4 setup reviewed by people who do it every week, contact Primal, a digital marketing agency in Bangkok, today.
Frequently Asked Questions About GA4 Migration (FAQs)
| Question | Answer |
|---|---|
| Can I still migrate from Universal Analytics to GA4? | No. Universal Analytics stopped processing data on 1 July 2023 and Google deleted the properties and their data from July 2024. Any website still without a GA4 property is collecting nothing, so the job now is a fresh GA4 setup rather than a migration. |
| How do I set up GA4 from scratch? | Create a GA4 property, add a web data stream, and install the Measurement ID through Google Tag Manager or directly in the site’s head section. Then define events, register parameters as custom dimensions, set data retention to 14 months, exclude internal traffic, link Google Ads and Search Console, and mark your key events. |
| What is the difference between GA4 and Universal Analytics? | GA4 is event-based and measures users across websites and apps, with privacy controls and machine-learning modelling built in. Universal Analytics was session-based, tracked website and app separately, and relied on views, goals and filters that GA4 replaces with events, key events and data filters. |
| Why is my GA4 data missing or incomplete after migrating? | Usually one of seven settings was skipped: events not recreated, parameters not registered as custom dimensions, retention left at 2 months, internal traffic not excluded, Google products not linked, key events not marked, or attribution not reviewed for Google Ads. Each is a few minutes in the admin panel. |
Join the discussion - 0 Comment