New traffic_source parameter in BigQuery

A new array of parameters, session_traffic_source_last_click, has been added, and it's replicating session attribution from GA4.

Previously: Analysts parsed the event_params array (which was costly and not always accurate) or used the collected_traffic_source parameter (which reflected the source of a specific event).

Now: BigQuery schema includes a copy of the last-click source from GA4. This should, in theory, simplify session attribution calculations.

In short, calculating attribution in BigQuery with raw GA4 data should now be more convenient.

If you work with GA4 to BigQuery exports, be sure to check out my SQL cheat sheet.