Q: I set utm_medium=social, so GA4 will file it under Organic Social — correct?

Q: I set utm_medium=social, so GA4 will file it under Organic Social — correct?

A: Common trap. GA4 doesn't read your UTM literally; it runs your medium through channel-grouping rules.

— 'social' as a medium lands in Organic Social only because GA4's default rule matches that string — but utm_source must also be a known social source or it can fall to 'Unassigned'.
— Paid social needs utm_medium = cpc/ppc/paid + a paid source, or it's mislabeled as organic.
— Check the actual mapping at Admin → Channel groups → Default channel group.

So your channel isn't whatever you type — it's what the rules decide.

TL;DR: UTMs are inputs; channel grouping is the rulebook. Match the rules, not your guess.

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