What is a key event?
A key event is a GA4 event marked as important to the site or app, such as a registration or purchase.
The event first needs to be recorded, then marked as a key event in the relevant configuration. A registration button appearing on a page does not establish that a click or completed registration is being tracked correctly.
An event count is different from a count of people
One person can trigger an event more than once. Counting settings also affect the reported result, so a key-event total should not simply be relabeled as the number of customers.
For a rate, identify the corresponding numerator and denominator. Sessions with a key event and users with a key event answer different questions.
Keep the definition consistent across sources
When comparing channels, use the same event definition and counting approach. Check session counts alongside the result: a few visits can produce a large percentage swing.
A recorded inquiry remains an inquiry until later evidence establishes its quality or a sale. Marking an event as important expresses a measurement choice; it does not establish the business value of every occurrence.
Sources and scope
Source-language entry records a source check on 2026-09-28. This adaptation preserves that provenance and does not represent a new audit of the cited pages.