These kind of teachers who leave such a great positive impact on the world can't be measured. How do we measure whether a teacher has a whole mind, heart and soul? That doesn't mean that we shouldn't make the effort to measure. After all, every teacher must be accountable that the student is receiving the quality and quantity of learning they ought to have. But being a teacher is more than that. It's more than top grades and nice things to put on their portfolio to earn that place in University. And it definitely isn't equipping our students so that they can be better than others.
Parker Palmer, John Hunter and the few who retire quietly without titles or credentials, but remembered by those whom they've taught and learned with. I hope I'll grow to be that kind of teacher. We teach who we are; whole teachers raise whole people.