We need inconspicuous cameras in all classrooms, one behind the teacher, one behind the students, running all the time. Student test scores are just secondary and derivative surrogates for the real thing: watching the actual performance of teachers, their interaction with their students, and the student response and engagement with the teacher. The tapes provide magnificent tools for not only evaluating teaching talent, but as tools to help teachers improve their performance. Is there a subjective ingredient in this kind of evaluation? You bet. But a lot of good (or bad) teaching does not translate directly in test scores --- the empathic and inspirational dimension of teaching can be appreciated and assessed only by experienced supervisors.