High-cardinality dimensions can cause data to aggregate under an "(other)" row. If data is condensed into the (other) row in a commonly viewed report in your Google Analytics 360 property, Google Analytics enables automatic expanded data sets. Automatic expanded data sets expand the data in the (other) row to give you a more complete picture of your data.
You don't need to take an action to use automatic expanded data sets. They are used automatically for frequently viewed reports in Google Analytics 360 properties, providing properties that have high-cardinality dimensions with a fuller picture of their data.
Analytics 360 disables automatic expanded data sets when no one in a property views a report in the past 60 days, at which point the data will condense back into the (other) row. If the report starts being commonly viewed again, Analytics 360 will trigger another automatic expanded data set. Keep this in mind if you notice data moving in and out of the (other) row.
Automatic custom tables don't support some dimensions. If a report includes one of the following dimensions, then Analytics 360 won't use an automatic custom table and you will still see the "(other)" row:
- Attribution dimensions (including Default channel group in the Traffic Acquisition report)
- Session Conversion Rate (for one specific Conversion)
- User Conversion Rate (for one specific Conversion)