GA4 + GTM Audit Checklist I Run Before Any CRO Test

Audit steps in order

Export the GTM container JSON and build an event map: trigger → tag → GA4 event name → business meaning. Delete duplicates first—they are the silent killers. For reference, see GA4 key events documentation.

Walk critical flows on staging with GA4 DebugView and Tag Assistant: homepage, pricing, form submit, thank-you, purchase or lead confirmation.

Check consent mode: if analytics storage is denied by default without a proper banner, organic traffic looks fine while conversions flatline. Related reading: The GSC Metrics I Put on a Board Slide (and Which I Ignore).

Organic attribution I trust

Exploration: organic session medium, landing page = page path, conversions = business events only. Branded filters applied separately. For reference, see Google Search Console performance report help.

Compare GSC clicks on non-brand queries to GA4 organic landing sessions—large gaps mean tracking or tagging broke, not ‘SEO stopped working.’

Document UTM hygiene for email and paid so organic is not credited for campaigns with missing parameters.

Handoff after the audit

Deliverable is a prioritized fix list: P0 broken conversions, P1 duplicate events, P2 naming cleanup. Engineering gets GTM version notes; marketing gets a one-page ‘how to read organic’ guide.

Re-test 72 hours after deploy. I do not close tickets on ‘tag published’—only on events firing in production reports.