In school year 2009–2010, the Bill & Melinda Gates Foundation launched the Intensive Partnerships for Effective Teaching initiative, a $290 million project aimed at improving student achievement through more-effective management and support of the teacher workforce. The foundation identified seven Intensive Partnership sites— three school districts and four charter management organizations (CMOs)—to implement reforms covering teacher evaluation, staffing, professional development, and compensation and career ladders over a six-year period.1 These reforms are intended, among other things, to improve teachers' overall effectiveness and to ensure that low-income minority (LIM) students have access to highly effective teachers. A detailed description of the initiative is available in a RAND report, Implementation: The Intensive Partnerships for Effective Teaching Through 2013–2014.2 As part of an evaluation of the Intensive Partnerships initiative, RAND Corporation researchers investigated the relationship between teachers' effectiveness in raising student achievement in mathematics and reading (the teachers' value added) and the demographic characteristics of the students the teachers serve. We measured whether, on average, LIM students were taught by more or less effective teachers than non-LIM students were. We examined the issue among teachers and students in grades 4 through 8 in four sites (Hillsborough County Public Schools in Florida; Pittsburgh Public Schools in Pennsylvania; Memphis City Schools in Tennessee; and Aspire Public Schools, a California CMO) and investigated whether site policies designed to improve LIM students' access to effective teachers have worked. We also explored differences in student access to effective teachers between schools and differences in access between classes within schools. We focused the analyses on the three years prior to the initiative's implementation and the four years following implementation.