Report all events with custom dimension not set (or empty)

Question

I have user-scoped custom dimension and want to see if this dimension is applied to all required events.

I've generated custom report with "Event action" - "Event value" fields and trying to filter it by "Custom dimension" field. The problem is that there is no such events - no events with empty "custom dimension" value.

Does filter requires custom dimension to be explicitly set (e.g. to empty string) or there is just no events with empty 'custom dimension' value ?

Answer 1

Got answer here: https://productforums.google.com/forum/#!msg/analytics/of_JM1g0lAM/tC59L07fVQgJ

Custom dimensions, like event dimensions, do not have a (not set) or empty value that can be queried. Only events with non-empty values will appear in your report. To get the rest, you need to get the all events total and subtract.

Answer 2

This may be an anti pattern, but technically, you could bypass this limitation by setting your dimensions to a default value.

{{MyCustomDimension}}-foo

Where your empty dimensions would display as -foo and forward.

If the dimension was supplied, you would expect to see it in analytics as the dimension value followed by -foo.

Take click events in google tag manager for example:

{{Click Element}}.{{Click Classes}}

In the example above, we can always expect click element to be defined, but not an elements class attribute.