In efforts to improve the quality of teachers and teaching, one tools used by policy makers is teacher professional development. Teacher professional development is a significant source of expenditures in federal, state, and local spending on K-12 education, and there is significant debate about the value of these expenditures and how best to design professional development. Recently there have been a number of rigorous studies of professional development programs to inform these debates. This panel focuses on recent evidence on the impact of different approaches to professional development on classroom practice and student achievement. The first two papers in this panel provide evidence on what is called content-focused professional development. For approximately two decades, there has been a strong belief that professional development should be designed to address teachers’ knowledge of specific content and how to teach it. A number of studies during this period indicated that teachers lack sufficient content knowledge, making content-focused professional development a logical policy intervention. In addition, among studies of different approaches to professional development programs, results appeared especially promising for content-focused programs (e.g., the randomized controlled trial of the Cognitively Guided Instruction program published in 1989). The third paper in this panel addresses an emerging approach to professional development that is encouraged in recent federal policy initiatives. Through the Race to the Top program and the new Elementary and Secondary Education Act flexibility waivers, states and districts are being encouraged to use approaches to professional development that are integrated with new systems for teacher evaluation. For example, the ESEA waiver program calls for “evaluation and support systems” with a number of features including “clear, timely, and useful feedback, including feedback that identifies needs and guides professional development.” The third paper in this panel will provide evidence on an approach to professional development that provides each teacher with several rounds of individual feedback and coaching focused on aspects of instruction that have been shown to correlate with student achievement gains. This work builds on accumulated evidence showing correlations between certain measures of instructional practice and student achievement gains. The proposed chair for the session contributes significantly to national policy debates regarding teacher quality. The proposed discussant has contributed to the literature on teacher quality and many other public policy topics, and brings extensive methodological expertise.