Teachers and their unions do not want test scores to count for everything; classroom observations are key, too. But planning a couple of visits from the principal is hardly sufficient. These visits may "change the teacher's behavior"; furthermore, principals may not be the best judges of effective teaching. So why not put video cameras in classrooms, and use the recordings as part of teachers' evaluations? This is a question that Tom Kane has been asking. Kane, an education and economics professor on leave from Harvard University, leads a massive initiative supported by the Bill & Melinda Gates Foundation that is developing new approaches to evaluating teachers, with high-definition, 360-degree cameras at the center. Three thousand teachers in six cities are participating; for doing so, they receive stipends and lots of feedback from experts. The Gates project is focused on using video only for teacher evaluation, not regular "monitoring." In many places, including Washington, D.C., collective bargaining agreements explicitly restrict the use of "electronic monitoring equipment." Teachers may scream about infringements on their "professionalism," but the author points out that effective teachers will have little to fear. Already, their expectation of complete autonomy--that they close their doors and do what they want--has been undermined by standards, tests, and other reforms of the modern era.