Source / Medium (GA4)

Source and medium are GA4 traffic dimensions that describe where users or sessions came from and the general type of channel associated with that visit. A source might identify a search engine or newsletter, while a medium might distinguish organic traffic from email. The exact interpretation depends on whether the report uses first-user, session, or event-related acquisition dimensions. For a small service business, consistent UTM tagging can make marketing links easier to compare, but incorrect tags can create messy reports. Source/medium is not the same as a lead's final sales origin, which may require records outside analytics.