I’m experiencing a significant discrepancy in the total user count between BigQuery and GA4. I’m using Shopify and Elevar for server-side tracking. Over one week, there is a 15% discrepancy, and over one month, it can be up to 30%.

Here’s the query I’m using in BigQuery:

select
count(distinct(user_pseudo_id)) as users
from
events_*
where
_table_suffix between ‘20240715’ and ‘20240721’

The BigQuery result is 21,627 users for the specified week but GA4 is 24,319(see attached screenshot).

I suspect that GA4 might be calculating total users differently compared to my query. This level of discrepancy is unusual as GA4 and BigQuery data are usually quite similar in my experience. I would appreciate any insights or suggestions on what might be causing this discrepancy and how to resolve it.

Additional Information:
Tracking Setup: Shopify and Elevar for server-side tracking
Time Frame: 15% discrepancy over one week, up to 30% over one month
Tools Used: BigQuery, GA4
Any help or advice would be greatly appreciated.