I don't think that's a good metric at all.
and the other way around. To me those metrics are useless and most of the times beside the point. Most of the interviews need to be done on an eye to eye basis with someone of the team and than there should be, as you mentioned, a technical discussions and even there it's hard to know if the current level is the correct judgment level.
Hiring people is hard and complex because it's value based and different companies and people have different values. So you need to design your system for your team / company anyways.
Maybe there are good studies on this how to create certain metrics .... I have to look it up :)