There was a ratings system like this in early days of Google but it was accompanied by a very explicit guideline for what each number means. IIRC 6 was demonst

There was a ratings system like this in early days of Google but it was accompanied by a very explicit guideline for what each number means. IIRC 6 was demonstrated mastery, 10 was "literally wrote the book on the topic." It wasn't for candidates, though, it was initially for interviewer stats and possibly maybe referred to for team transfers. (the current version is in a completely reworked system and on a four-point scale that includes "interested" and "currently learning" so really only a two point scale of claimed knowledge)