Why GA4 Is Different — The New Data Model
The event-based model that replaces sessions and pageviews — and why it is actually more powerful
GA4 is not an upgraded Universal Analytics. It is a completely different data model built for a multi-device, privacy-first world. Understanding the difference explains why reports look different and how to use the new power.
Sessions vs events
Universal Analytics measured journeys. GA4 measures actions.
Universal Analytics grouped everything into sessions — visits with a start and end. GA4 records individual events: every scroll, click, video play, form interaction. There are no sessions in the raw data — GA4 constructs them from events. This means you can ask questions that were impossible before: "How many users scrolled past 50% on the pricing page before clicking the CTA?"
The event model
- Automatically collected events — Page views, scrolls, outbound clicks, site search, video engagement — collected by the GA4 tag automatically.
- Enhanced measurement events — File downloads, scroll depth, form submissions — enable in the GA4 data stream settings.
- Custom events — Anything specific to your business. Button clicks, feature uses, milestone completions. You define and implement these.
What GA4 cannot do (yet)
- Historical data from Universal Analytics — GA4 does not import UA data. If you need historical comparison, keep UA exports.
- Perfect attribution — GA4's attribution models are probabilistic, not deterministic. Privacy restrictions mean some conversions are unattributable.
Try this
Open your GA4 property and navigate to Reports → Engagement → Events. Look at the top 10 events for the last 30 days. Are they the ones that matter for your business? The absence of a critical event is a measurement gap — note it as something to implement.