A collaborative effort among six partner universities and the Urban Institute, CALDER's purpose is to inform state and local education policy through analysis based primarily on state-specific administrative data on individual students and teachers over time. Our ultimate interest is in student outcomes with particular attention to how outcomes differ for subgroups of the population. Given the major role that teachers play in determining student outcomes, the primary focus of our research effort will be on teachers, especially who teaches which students, and on the determinants of teacher quality, as evidenced by student achievement gains.