What Is Universal Analytics?

Universal Analytics (UA) was Google's previous analytics platform, replaced by GA4 after Google sunset it for standard properties in mid-2023. UA used a session-based measurement model, in contrast to GA4's event-based model, and is referenced today mainly as a comparison point for teams migrating historical reporting logic.

Teams that built years of reporting logic around UA’s session-based model often find GA4’s event-based approach requires rethinking rather than a like-for-like migration: a ‘session’ and a ‘pageview’ aren’t tracked the same way across the two platforms. Understanding what changed matters most when validating that a GA4 setup is actually capturing the same business events UA used to, rather than assuming parity.