In July 2011, Bill Gates told the "Wall Street Journal," "I'm enough of a scientist to want to say, "What is it about a great teacher?"" As a "practitioner" of sorts, the author has wondered the same thing for 15 years. The K-12 school sector generates little empirical research of any sort. And of this small amount, most is targeted to policymakers and superintendents, and concerns such matters as the effects of class size reduction, charter school attendance, or a merit-pay program for teachers. Why is there virtually no empirical education research meant to be consumed by the nation's 3 million teachers, answering their questions? Those 3 million teachers generate about 2 billion hour-long classes per year. People do not know empirically which "teacher moves," actions that are decided by individual teachers in their classrooms, are most effective at getting students to learn. The author argues that relative to education policy research, there is very, very little rigorous research on teacher moves. Bill Gates knows the reason for this is more than a lack of raw cash; it's also about someone taking responsibility for this work. The author contends that there are a number of other barriers. The first is a lack of demand. Moreover, neither policy camp, reformers nor traditionalists, care much about research into teacher moves, either. The final barrier to research on teacher moves is the divide between practitioners and researchers. In this article, the author proposes a typology of trials in studying teacher moves, delineating phases in a continuum. He proposes that each of the nation's 1,200-plus schools of education and teacher prep programs conduct one randomized trial on a teacher move each year: Phase 1, Phase 2, or Phase 3.