Well, it's very vague because there aren't hard lines for the measure. That's inherent to that level of taxonomy. It exists, but it's rather fuzzy and inexact, with lots of overlap, and they keep changing the classifications.

To me, the Elbe-Germanen and the Bajuwaren are distinct races, but they often get lumped in with Germanics or Alpines, or whatever, and they're all European or white.

You could also go by eye color or height, or whatever. You can identify people by any measure you choose, with more or less validity.