To improve the U.S. education system through more-effective classroom teaching, in school year 2009-2010, the Bill and Melinda Gates Foundation announced four Intensive Partnership for Effective Teaching sites. The Intensive Partnerships Initiative is based on the premise that efforts to improve instruction can benefit from high-quality measures of teaching effectiveness. The initiative seeks to determine whether a school can implement a high-quality measure of teaching effectiveness and use it to support and manage teachers in ways that improve student outcomes. This approach is consistent with broader national trends in which performance-based teacher evaluation is increasingly being mandated at state and local levels. To test the theory in practice, the foundation sought partnership sites. It selected three school districts--Hillsborough County Public Schools in Florida, Shelby County Schools in Tennessee, and Pittsburgh Public Schools in Pennsylvania. The foundation also selected four charter management organizations--Alliance College-Ready Public Schools, Aspire Public Schools, Green Dot Public Schools, and the Partnerships to Uplift Communities, all in California. To evaluate Intensive Partnership implementation, researchers from the RAND Corporation and the American Institutes for Research interviewed annually central office staff at each site and teachers and other staff in a sample of schools for each site. They also used data from annual teacher and school-leader surveys and documents that the sites and the foundation provided. This report summarizes the implementation status of key reform elements at each site when the Intensive Partnerships initiative launched and five years later in the spring of 2014. [For the executive summary, see ED580307. For Appendixes D and E, see ED580322.]