GA4 vs. Universal Analytics: What Changed
GA4 replaced Universal Analytics with an event-based data model, different metric definitions, and no built-in bounce logic.
What it means
Universal Analytics (Google's previous analytics platform, sunset in mid-2023) tracked pageviews and sessions as its core unit. GA4 rebuilt everything around events — a pageview, a click, a purchase are all just events with different names and parameters. That shift changed how several familiar metrics are defined, including bounce rate, sessions, and conversions.
Why it matters
If you have old reports, benchmarks, or habits from Universal Analytics, several of the numbers you remember don't translate directly. Bounce rate, users, and conversions all mean something at least somewhat different in GA4, so comparing a current number to a pre-2023 memory can lead you to the wrong conclusion about whether things have actually changed.
ask datanephew
My numbers look totally different than my old Google Analytics — did something break?
Ask datanephew to explain which specific metric changed — GA4 redefined several core numbers when it replaced Universal Analytics, and that alone explains most jumps.
Can I get my old Universal Analytics history back?
datanephew can't recover UA data since Google stopped processing it, but it can help you understand your GA4 numbers on their own terms going forward.