User ID Tracking Implementation
Implement User ID tracking for cross-device measurement. Learn how to track authenticated users across devices.
User ID Tracking Fundamentals
User ID tracking connects sessions from the same user across devices and browsers. Essential for accurate user measurement.
Benefits of User ID
Cross-device tracking, accurate user counts, better attribution, and improved audience building.
Implementation Requirements
User authentication system, unique user identifiers, and proper User ID implementation in GA4.
GA4 User ID Setup
Enable User ID in GA4 settings, send User ID with events, and create User ID view for analysis.
Privacy Considerations
Don't send PII as User ID, hash identifiers if needed, and respect user privacy preferences.
Analysis with User ID
Compare User ID vs non-User ID data, analyze cross-device behavior, and improve attribution.
Common Use Cases
Subscription services, membership sites, ecommerce with accounts, and mobile apps.
Best Practices
- Use non-PII identifiers
- Implement consistently
- Test across devices
- Document implementation