This report examines the experiences of three large urban school districts (and part of a fourth) that raised academic performance for their districts as a whole, while also reducing racial differences in achievement. Educational challenges included low achievement, political conflict, inexperienced teachers, low expectations, and lack of instructional coherence. The research involved case studies of these districts and comparisons with other districts that had not yet seen similar improvements. Researchers conducted site visits to each district, interviews with key district-level actors, focus groups, teachers, and principals, as well as document reviews. Results indicated that political and organizational stability over a prolonged period and consensus on educational reform strategies were necessary prerequisites to meaningful change. Districts faced systemic challenges above the individual school level. They lacked clarity regarding instructional standards and had a wide variety of educational strategies and instructional approaches. To achieve instructional coherence, districts adopted or developed their own, uniform, relatively prescriptive reading and math curricula for the elementary grades. The districts used data to guide instruction and decision making. Leaders in these districts invested substantial amounts of time, effort, and resources in changing district culture and creating a systemwide consensus for reform. Appendices contain profiles of the case study and comparison districts, as well New York City's Chancellor's District. (Contains 26 references.) (SM)