Enhanced Conversions in Google Analytics (EC for GA4) improves cross-device attribution and measurement accuracy using hashed first-party data (emails, phone numbers). While valuable for marketers, enabling this feature has irreversible consequences for GA4 data exported to BigQuery.

The Fundamental Change

When you turn on EC for GA4, if you have the GA4 BigQuery export engaged, GA4 starts sending data differently to BigQuery. Instead of all the raw data you’d normally expect, some fields are modified or omitted. This means:

  • Permanent Data Shift: The changes are irreversible. Once data is exported under Enhanced Conversions, you can’t revert to the old format.
  • Modified Metrics: Some identifiers like user_pseudo_id or session details might be missing or altered, affecting how you measure user behavior and campaign performance.

How EC for GA4 impacts reporting on GA4 exported data in BigQuery

  1. Event Data vs. Identifiers:
    • You still see basic event counts (e.g., pageviews and clicks).
    • However, EC for GA4 permanently disables the export of user_id values to BigQuery.
    • New table structures are introduced, breaking existing reporting.
    • Without key identifiers, tying events to specific users or sessions becomes challenging, impacting attribution and detailed analysis.
  2. Reporting Differences:
    • EC for GA4’s irreversible changes in BigQuery exported GA4 data lead to additional discrepancies between what you see in GA4 and what’s stored in BigQuery.
    • Existing discrepancies could be (i) GA4 reporting on modeled data to fill in gaps, (ii) GA4’s estimations in reporting (HyperLogLog), or (iii) GA4 reporting impacted by high cardinality, sampling, data thresholds or (other) row instances.

Consider leveraging Google Ads’ Enhanced Conversions for web instead

With Google Ads’ Enhanced Conversions for web hashed first-party data is sent directly to Google Ads (e.g., via Google Tag Manager). This approach allows Google Ads to benefit from improved conversion tracking accuracy, while also allowing you to preserve the integrity of your GA4 BigQuery exported data by not engaging in EC for GA4.

NOTES:

  1. EC for GA4 is “…part of an open beta and is subject to change” – yet another reason to not engage it given how much it impacts your GA4 BigQuery exported data.
  2. Be sure your privacy policy, and the configuration of your consent management platform (if you have one), address user consent relative to sending their hashed first-party data to any third party.
GA4 Enhanced Conversions: The BigQuery Trade-Offs You Can’t Reverse