Google wants to move on from Google Universal Analytics (UA) to Google Analytics 4 (GA4), the culmination of what once was the company’s App + Web service that unified analytics tracking across digital assets (i.e., websites, mobile sites, and apps). There isn’t an available timeline yet, but it pays to be an early adopter.

One key reason is to be able to collect historical data that works on GA4 right away. Instead of waiting until you’re forced to migrate and finding that some setups you’ve got on UA won’t work the same way in GA4, it’s best to start dual-tagging now and collecting data on both.

This article will discuss at a high level what’s involved when transitioning your event tracking from UA to GA4 via Google Tag Manager (GTM).

Google Analytics 4 vs. Universal Analytics

Fortunately, Google Analytics 4 event tracking isn’t completely different from Universal Analytics. What’s different is how they collect data. 

In UA, the basic unit of measurement is a hit, a bundle of descriptors recording user interaction. The two most common types are pageviews and events.

The thing is, in GA4, everything is an “event.”

In UA, an event hit, for instance, has a Category, Action, and Label (and the hit has its own type). For example, an event type hit would include:

• Event category: video playing
• Event action: progress of video playback
• Event label: 50%

In GA4, the above descriptors are reduced to a bundle of the event and event-parameter(s), like so:

• Event: Video_progress event
• Event-parameter 1: video_title
• Event-parameter 2: video_percent

Obviously, you not only want to set up a dual-tagging system where the events you’re tracking are properly sent to both UA and GA4, but you also want to get used to the GA4 approach, as it will eventually be the one that remains.

Dual-Tagging via Google Tag Manager

If you’re using GTM on your site, you can use that to set up GA4 tags. To dual-tag, you’ll need to create equivalent GA4 tags for existing UA tags, but the good news is that in most cases, you can use the same variables and triggers in your UA configuration to generate GA4 events.

In GA4, there are four types of events:

• Enhanced-measurement
• Automatically-collected
• Recommended
• Custom events

You’ll need to map existing events in UA to new ones in GA4, checking if there are corresponding ones you can use in GTM. First, check if there is an equivalent enhanced measurement event, then an automatically-collected event, and lastly, a recommended event. If GTM can’t match an existing UA event to one of those three GA4 events, you’ll need to create a custom event.

If you need in-depth assistance with dual-tagging or migrating event tracking from UA to GA4 via GTM — or even trickier, gtag.js! — we’re here to help.