Google Analytics - Problem with custom variable - Data look not precise

Question

I use a custom variable to store the username of who is visiting my site.

So I access the custom variable report to list all the values of a custom variable, and have a look at the whole list of users.

I would expect a list of 30 users, while the list includes only 5.

This is not any filter in place (the timerange too is set on a long period that does not limit the list of users).

Is there anything I should consider that is faking the list of users/the list of values of the custom variables?

Maybe very short sessions are not considered in the list?

For example, is this post from 2011 still valid?

Answer 1

Wait: are you storing username info in your analytics so you can track and visualize behavior of specific people?

If yes: you are violating Google's TOS. And you should erase your Google Analytics property data. Not just the view, but the whole property. That's mandatory (if Google catch you do that, it's even worse).

The only way you can track logged in users is by using UserID built-in function https://developers.google.com/analytics/devguides/collection/analyticsjs/user-id (the UserID would be an unique numeric identifier that Google uses just for collect different cookies of same users under the same recipient).

Don't use custom dimensions to distinguish between users. You can only collect anonymous and aggregate data.