Google Analytics 4 (widely referred to as GA4) is the successor to Universal Analytics (UA).

There are five major differences between UA and GA4.

    1. How users are tracked
      UA tracks user interaction via sessions (within a time frame), while GA4 tracks events (what users do).
    2. How data is collected and aggregated
      UA uses a tag per property (websites/apps) with separate configurable views. GA4 has properties that allow collection from multiple collection points (data streams) and aggregates them to enable consolidated app + web reporting (unified measurement).
    3. User privacy
      When UA was first built, data privacy wasn’t even a ‘thing’. GA4 has been designed, from the ground up, with privacy in mind – it uses machine learning and AI to create insights rather than relying on cookies and/or user identifiers.
    4. Reporting
      UA has a range of sort of useful genereic ‘top level’ reports ‘out of the box’ and allowed very limited customisation. GA4 has  range of configrable ‘top level’ reports and allows much greater strategic reporting flexibility – Which is to say that some of the reports you’re used to looking at in UA may not available in GA4, and a lot of data not previously available in UA is now available (with some custom configuration).
    5. Data Retention
      UA allows historical data to be kept for 50 months. GA4 retains unaggregated data for a maximum of 14 months.