Last Updated: December 6, 2024

GA4 Event Rate 100% means user key event rate of 100% or session key event rate of 100% or both.

In GA4, all the metrics and dimensions used in a report must share the same scope to provide meaningful data.

The screenshot below shows a user key event rate of 100% for each event name. 

You see such a result because the ‘event’ scope of the ‘event name’ dimension does not align with the ‘user’ scope of the metric ‘user key event rate’.

In GA4, all the metrics and dimensions used in a report must share the same scope to provide meaningful data. 

The ‘event name’ dimension is event-scoped, meaning it applies to individual events rather than users. 

However, the ‘user key event rate’ is a user-scoped metric, which measures the percentage of users who triggered one or more key events (aka conversions).

This mismatch in scope can lead to misleading or redundant results, such as showing a 100% user key event rate for all events.

The same reasoning applied to the ‘session key event rate’ metric.

The following is a more detailed explanation:

The user key event rate is the percentage of users who triggered one or more key events.

The ‘user key event rate’ metric has user scope.

This means this metric is calculated only once per user, regardless of how many times a user triggered a key event.

Consider the following scenario:

You have set the ‘newsletter signup’, ‘file download’, and ‘purchase’ events as key events in GA4.

Over the course of a week, your website has 2000 unique users.

Out of 2000 users, 25 users made a purchase at least once during that week.

Out of those 25 users, 20 users made several purchases on different days within the same week.

Out of 2000 users, 25 users signed up for your newsletter.

Out of those 25 users, 15 users signed up for your newsletter as well as downloaded files.

Calculation of ‘User Key Event Rate’:

The ‘User Key Event Rate’ metric focuses on whether each unique user triggered a key event and not on the number of key events per user or type of key event (‘newsletter signup’, ‘file download’, and ‘purchase’).

So, the total number of users who triggered one or more key events in a week

= 25 users who made a purchase at least once during the week + 25 users who signed up for your newsletter during the week.

= 50 users

So, assuming no overlap between the purchasers and newsletter sign-ups/file downloads, 50 users triggered one or more key events in a week.

Therefore, the user key event rate is calculated as = 50 / 2000 = 2.5% .

The ‘user key event rate’ metric already considers all key events, regardless of individual event names.

So, querying the ‘event name’ dimension with the ‘user key event rate’ metric provides redundant information like a 100% user key event rate.

Since the user key event rate considers any key event for the chosen user, it won’t provide specific insights into the key event rate for a particular event named in the “event name” dimension.

This can lead to misinterpretations if you assume the user key event rate only reflects the named event.

You cannot analyze the key event rates for specific events using the ‘user key event rate’ metric.

The same reasoning applies to the ‘session key event rate’ metric.

To ensure accurate reporting, match the scope of metrics and dimensions used in your report. 

For example, if you are using a user-scoped metric like ‘user key event rate’, you should pair it with user-scoped dimensions like ‘First user default channel group’:

Similarly,

If you are using a session-scoped metric like ‘session key event rate’, you should pair it with session-scoped dimensions like ‘Session default channel group’:

That’s how you can avoid showing the GA4 event rate 100% in your reports.