Definition
What is Default Channel Group?
The default channel group is GA4's built-in classification of traffic into channels like Organic Search, Direct, Referral, Paid Search, and Organic Social, based on the source, medium, and campaign of each session. GA4 applies a fixed set of rules to assign each session to exactly one channel. Custom channel groups can be created to reclassify traffic, such as isolating AI assistant referrals.
Why it matters
Channel groups are the lens through which most marketers read GA4, so misclassified traffic (for example AI referrals landing in Direct) can hide where results actually come from.