Does GA4 Track Source/Medium for All Events? Think Again!

🤔 Think GA4 tracks source/medium for all events? Think again! Learn which events GA4 prioritizes and how to optimize your setup. 👇

The source and medium for non-key events in GA4 are usually "(not set) " 😮 

This is because for non-key events, GA4 typically does not automatically capture source and medium information.

In GA4, source and medium information is most relevant at points of entry and key conversion actions.

Since source and medium information is most relevant at points of entry, GA4 automatically captures this information for certain non-key events that mark significant entry points in the user journey.

These entry-point events typically include 'first_visit', 'session_start', and other similar non-key events.

For non-key events that occur early in the user journey but are not specifically designated as entry points (like custom events triggered early), you would need to configure GA4 or use Google Tag Manager to explicitly capture source and medium information.

Non-key events that occur deeper within the user journey (such as interactions with specific features, content, or elements on the site) typically do not automatically capture source and medium information.

There is no official explanation from Google regarding why they don't capture source and medium information for every single event.

While there is no official explanation, it is reasonable to infer that it would significantly increase the volume of data collected, which can lead to increased storage requirements and processing overhead.

Also, capturing such information might not provide additional valuable insights.

However, GA4 does automatically capture source and medium information for key events.

Since key events are significant user interactions (like conversions, purchases, or sign-ups) where the source and medium of the traffic are highly relevant for attribution analysis, GA4 automatically capture source and medium information.