Our company is in the process of transitioning from UA to GA4. We use GTM to handle all of our events, and we're checking event volume side-by-side to be sure we can smoothly transition our reporting when we complete the process.

As part of this transition, we're also playing around with conversions in GA4 to try to use more of its built-in capabilities. We noticed that a particular event had equal volumes between the two platforms at first, but suddenly the GA4 event volume dropped by 9% when we toggled off that event as a conversion. When we toggled it back on, the event volumes are equal again. This particular event is set as a goal in UA, though we don't use that capability.

We're using BigQuery exports of the data to compare event volumes, so this isn't an issue with the UI or sampling or anything.

Why would deciding that an event counts or does not count as a conversion impact the observed event volume?

1 Answer 1


There are different counting methods in GA4 that weren't there in UA.

Basically in UA, a conversion would fire once per session but in GA4 we now have the ability to mark conversions every time an event happens or once per session.

To figure out which you are doing, go to Admin >> Conversions and click the stacked three-dot icon next to one of the events listed. You should see the Change counting method option. Here is where you can set your method.

I suspect you have once per session selected for the conversion rather than once per event and that is why there is a large discrepancy.

  • To clarify, the counts of conversions is irrelevant. The discrepancy is with the number of hits to the underlying event. We have Event A which exists on both platforms. It's marked as a goal in UA and a conversion in GA4. The number of hits to Event A in both platforms is equal. Next, I toggle off Mark as conversion for Event A in GA4 in Admin >> Data display >> Conversion, and now the number of hits to Event A is 9% lower in GA4. Finally, I toggle Mark as conversion back on for Event A in GA4, and the number of hits to Event A is equal again between both platforms.
    – benande
    Feb 16 at 17:07

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.