Say that you own an auto repair facility. You have 10 mechanics who have applied, and all ten have previous experience on their resume.

How would you interview them, so as to choose the best candidate the first time?

I won't have a great answer since I have no experience in the area. But I would probably ask them to repair something, leave them alone and come back in 2 hours. Pick the mechanic that repaired it the best. I would not stare over their shoulder while they worked.

For the music teacher I would have them record the piece, and send in the best take. I wouldn't demand they get on stage and play the piece.