How do I track cross-domain conversions accurately in GA4 without double-counting users?

All answers to this question.

GA4 actually makes this easier than Universal Analytics, but it’s hidden. Go to Admin > Data Streams > [Your Stream] > Configure Tag Settings > Configure Your Domains. Add both domains there. The most important part is ensuring you don't have a "Referral Exclusion" issue. Also, make sure both sites are using the same G-XXXXXX Measurement ID via the same GTM container if possible. If you see _gl parameters in your URL after clicking a link to the second domain, then the linker is working correctly!

   Answered 2024-05-06 by Kimberly Vance

Are you seeing a lot of "(direct)" traffic in your reports for the second domain? That’s usually the biggest red flag that the session is breaking.

   Answered 2024-05-07 by Steven Miller

• Steven, yes! Almost 60% of our bookings are showing as "(direct)" which is impossible given our ad spend. It’s definitely a session break. I checked the "Configure Your Domains" section Kimberly mentioned, and I realize I only had the main domain listed there. I’ll add the subdomain now and hopefully, that fixes the attribution leak.

     Commented 2024-05-08 by Brandon Smith

Don't forget to test this in "DebugView" within GA4. It’s the only way to see the events firing in real-time across the domain hop.

   Answered 2024-05-09 by Nancy Drew

• DebugView is a lifesaver. It’s much more granular than the old "Real-Time" reports and helps verify that the user_id stays consistent throughout the journey.

     Commented 2024-05-10 by Kimberly Vance