Google Analytics 4 is now Google's essential measurement tool. Since Universal Analytics was decommissioned in July 2023, every business that wants to measure its web performance needs to master GA4. But GA4 is fundamentally different from its predecessor. This guide explains everything.
What is Google Analytics 4?
Google Analytics 4 (GA4) is the fourth major version of Google Analytics, launched in October 2020. Unlike previous versions based on a sessions and pageviews model, GA4 is built on an event-based data model: every interaction on your website or app is an event.
This deep redesign allows GA4 to:
- Measure both websites and mobile apps in a single property
- Track users across different devices and sessions (cross-device, cross-platform)
- Leverage artificial intelligence to fill data gaps caused by cookie refusals
- Offer enhanced privacy compliance with modern regulations (GDPR, CCPA)
The fundamental difference from Universal Analytics
In Universal Analytics, everything was structured around sessions. A session was a group of user interactions during a given period. Data was organised into hits (pageviews, events, transactions).
In GA4, everything is an event. A pageview is an event. A click is an event. A purchase is an event. This uniformity simplifies data collection and analysis, but requires a new way of thinking.
| Universal Analytics | Google Analytics 4 |
|---|---|
| Sessions + pageviews | Events only |
| Views | Data streams |
| Goals | Conversions |
| Fixed reports | Free data exploration |
The GA4 event model
In GA4, events fall into four categories:
1. Automatically collected events — gathered without any configuration: page_view, session_start, first_visit, user_engagement...
2. Enhanced measurement events — enabled with a single click in the interface: scrolls, outbound clicks, site searches, YouTube video interactions, file downloads.
3. Recommended events — suggested by Google based on your industry. For example purchase, add_to_cart, begin_checkout for e-commerce.
4. Custom events — created based on your specific needs. These are what give you the real added value.
Essential reports in GA4
Standard reports
GA4 offers ready-made reports in the "Reports" section:
- Acquisition: where your users come from (organic, paid, direct, social...)
- Engagement: which pages users browse, how long they stay
- Monetisation: e-commerce revenue, subscriptions
- Retention: user loyalty and lifetime value
Explorations (formerly Analysis)
The Explorations workspace is GA4's most powerful tool. It lets you create ad-hoc analyses:
- Free-form exploration: pivot table on any dimension/metric combination
- Funnel exploration: visualise and analyse your conversion funnels
- Path exploration: understand your users' navigation paths
- Segment overlap: create user cohorts and compare their behaviours
How to configure GA4 correctly
A good GA4 configuration involves several steps:
- Create a GA4 property in your Google Analytics account
- Configure data streams (web, iOS, Android depending on your ecosystem)
- Implement the GA4 tag via Google Tag Manager (recommended) or directly in the code
- Enable enhanced measurement to automatically collect key interactions
- Configure custom events via GTM for your specific tracking needs
- Define conversions by marking critical events (forms, purchases...)
- Link Google Ads for a complete view of your campaigns
Expert tip: Don't dive into GA4 without first defining a measurement plan. What KPIs do you want to track? Which events are critical for your business? This strategic step will save you hours of reconfiguration.
Common mistakes to avoid
Duplicating events: if both GA4 and GTM send page_view, your data will be skewed. Check your configuration carefully.
Neglecting consent: in Europe, you must implement Consent Mode v2 to remain GDPR-compliant and avoid losing data in modelling mode.
Using standard reports as your only truth: Explorations are far more powerful for analysis. Take the time to master them.
Ignoring data quality: a well-configured GA4 must be validated regularly. Use the DebugView report during your deployments.
Conclusion
Google Analytics 4 is a powerful but demanding tool. Mastering it requires understanding the event model, rigorous configuration and regular data quality checks. Businesses that invest in a proper GA4 setup gain a real competitive advantage in driving their marketing decisions.
If you need help configuring or auditing your GA4, I'm available for a free 30-minute consultation.