Quickly Determine the Scope of Any GA4 Dimension or Metric

Here is how you can quickly determine the scope of any dimension or metric in GA4 without using 'GA4 Dimensions and Metrics Explorer' or 'API Reference documentation'.

This will help you avoid mixing dimensions and metrics of different scopes in your reports and skewing analytics reports.

In GA4, a scope represents a different level of data aggregation and context.

GA4 supports three different scopes: user, session and event scope.

User-scoped dimensions are prefixed with ‘First user’ (like ‘First user source/medium’).

There are some user-scoped dimensions that are not prefixed with 'First user' like 'country', 'city', 'Signed in with user ID' etc.

You can determine the scope of such dimensions by understanding that user-scoped dimensions typically represent user attributes that remain relatively constant.

For example:

>> Country.

>> City.

>> User ID.

>> Membership Level.

>> Subscription plan.

If a dimension reflects a user characteristic unlikely to change frequently, it most likely has user scope.

Session-scoped dimensions are prefixed with ‘Session’ (like ‘Session source/medium’).

Event-scoped dimensions do not have a prefix (like ‘source/medium’).

That’s how you know they are event-scoped.

GA4 does not have user-scoped metrics in the traditional sense, even when these metrics aggregate data specific to individual users across all their sessions.

GA4 built-in metrics are typically session-scoped.

This means they focus on quantifiable aspects of user behaviour within individual sessions on your website or app.

Most built-in metrics in GA4 have a session scope, but for some odd reason, GA4 allows creating custom metrics only with event scope.

So, if you see any custom metric in a GA4 report, it has an event scope.