Attribution in Google Analytics 4 (GA4) is crucial for understanding the role of each touchpoint in driving conversions. GA4 offers various attribution models depending on the scope of the report, such as user acquisition source, session source, or event source. Unlike Universal Analytics, which used a last non-direct click model, GA4 provides more flexibility and detailed attribution options.
Key Changes and Features in GA4 Attribution:
- Session Source: Determines the source that started the session. If a direct visit starts a session, the source of the previous session is attributed unless no other source is found within the lookback window (default is 90 days).
- First User Source: Shows where the user came from for the first time. This is a user attribute and uses the last non-direct click model.
- Event Scope Attribution: Events have replaced sessions as the fundamental unit of data collection in GA4. Attribution models can be set in the property settings and are retroactive.
- Attribution Models: GA4 offers several pre-defined models, including a default data-driven model. Changes to the attribution model settings are retroactive.
- Lookback Window: Determines how far back a touchpoint is eligible for attribution credit. The default is 90 days, but it can be changed. The first user source has a separate lookback window setting (default 30 days).
- Cookie Expiration and Data Retention: GA4 cookies have a standard expiration of 24 months, but this can be adjusted. Data retention is set to 14 months by default but can be extended in the paid version.
- Conversion Export to Google Ads: GA4 offers flexible options for exporting conversions to Google Ads, allowing attribution only to Google Ads or across all channels.
- Model Comparison Tool: Allows comparisons of different attribution models in the Advertising section, using either interaction time or key event time methods.
- Attribution Paths Report: Provides detailed data on the number of interactions and days to key events, with visualization options for different attribution models.
- Use of Scopes in Reports: GA4 uses session, user, and event scopes for source dimensions, which can sometimes lead to confusing reports if mixed incorrectly.
- Modeled and Blended Data: GA4 enriches data collected by the tracking code with modeled data, providing a more complete picture of user behavior, especially for cross-device tracking.
Important Considerations:
- Non-Direct Principle: All models do not assign value to direct visits unless there is no other interaction on the path.
- Ads-Preferred Models: Assign the entire value of the key event to Google Ads interactions if they occur in the funnel.
- Lookback Window Changes: These changes are not retroactive and apply only from the moment of the change.
- Data Retention: User-level data is deleted after the retention period unless exported to BigQuery.
- Blended Reporting Identity: Combines User-ID data with Client-ID and user-provided data for more complete reports.
GA4 aims to provide a more accurate and comprehensive understanding of user interactions and conversions, supporting better decision-making in online marketing.
