Sessions count in GA4 is quite bigger than events_intraday table in bigQuery

Question

Issue

• For example, GA4's sessions number of November is 559,555 take from (Report / Acquistion / Traffic Acquistion). But if I calculate session number from bigquery table, it is 468,991.
• There are big different. I guess bigquery's number close to our actual traffic and google analytics 360 number.
• Actually this is start from we implemented ecommerce event in our site. But we not sure this is related or not.

question

• GA4's screen number and data in bigquery should be same (or close)??
• How can we solve this issue? We would like to have close number.

FYI

We used this for calculating session number in bigquery.

SELECT
  HLL_COUNT.EXTRACT(
    HLL_COUNT.INIT(
      CONCAT(
        user_pseudo_id,
        (SELECT `value` FROM UNNEST(event_params) WHERE key = 'ga_session_id' LIMIT 1).int_value),
      12)) AS session_count,
FROM `bigquery-public-data.ga4_obfuscated_sample_ecommerce.events_*`

https://developers.google.com/analytics/blog/2022/hll

I'd really appreciated it if you guys give us an advice.

Hyperextension

Answer 1

The answer can be found in the Google documentation in short: Big Query is more precise whereas the GA4 browser uses estimates. Also, not all sessions are included in Big Query like Google Signals.

Aegean