GA4, one year after the forced migration. What actually broke.

Universal Analytics stopped processing data on 1 July 2023. July 2024 is the first full year on GA4-only. Instead of a takes piece, here is the list of questions we have answered for clients in the last 12 months, roughly in descending frequency.

Q: Why do my GA4 numbers not match my ad platforms?

Three reasons, in order of size. (1) Attribution model difference. GA4 defaults to data-driven, Meta to last-click-within-window. (2) Modelled conversions. GA4 fills consent-denied traffic with a model, ad platforms use their own. (3) Timezone and conversion window mismatches. Expect a 15 to 40% gap even when everything is configured correctly.

Q: Where did my bounce rate go?

GA4 has bounce rate since mid-2022 but defines it as the inverse of engagement rate. It is not the same metric as UA bounce rate. Year-over-year comparisons across the switch are not valid. Most teams have stopped using bounce rate as a KPI and use engagement rate + session duration instead.

Q: Why are my conversions different in GA4 vs Search Console?

Different data sources. Search Console counts clicks from Google search; GA4 counts sessions attributed to organic Google. The gap is largely unassigned and direct traffic that was actually organic (lost UTMs, redirects that strip referrer, iOS Mail link protection).

Q: The BigQuery export is free, why would I not use it?

You should. BigQuery export adoption in our client base went from 12% (July 2023) to 61% (July 2024). The only reason to not use it is if nobody on the team writes SQL. Even then, tools like ThoughtSpot and Looker Studio read BigQuery natively.

Q: What is the one setting most teams have wrong?

Data retention. GA4 defaults to 2 months. For most businesses it should be 14 months (the maximum for free accounts). Change it in Admin → Data Settings → Data Retention. Existing data before the change is not retroactively kept longer.

Q: Is GA4 reliable enough for revenue reporting?

As a single source of truth, no. As one source in a triangulated picture (GA4 + warehouse + ad platforms), yes. We recommend BigQuery as the source of truth and GA4 as the UI.

Sources: internal client FAQ log, July 2023 to July 2024; GA4 data retention documentation.