Event, Session, and User Scope in GA4
GA4 data lives at the event, session, or user level, and mixing those scopes causes odd-looking totals.
What it means
GA4 tracks nearly everything as an event, but each piece of data attached to an event has a "scope" — it belongs to that single event, to the whole session it happened in, or to the user across all their visits. A custom parameter scoped to an event won't automatically apply to the rest of that session or user, even if it feels like it should.
Why it matters
This is one of the most common reasons a custom report comes back with blank rows or numbers that don't add up the way you'd expect — you're often combining a metric and a dimension that live at different scopes. It's a technical detail, but it's the real explanation behind a lot of "this report looks broken" moments.
ask datanephew
Why does this report show blanks for some rows?
Ask datanephew to look at the specific report — a scope mismatch between what you're counting and what you're grouping by is a common, fixable cause.
Can I just ask for the numbers without worrying about this stuff?
Yes — describe what you want to know in plain language and datanephew handles picking dimensions and metrics that actually go together.