This report synthesizes the findings of four studies that focused on school districts as the center of focus for school-improvement efforts. The studies did not examine school systems that had been high performing for a long time; rather, they took their data from districts serving high percentages of students who typically struggle but were improving. A chapter is devoted to a summary of each of the four studies. Each study differed in scope and methodology, but the results identified some elements common to most of the improvement efforts: (1) State accountability programs drove the change efforts; (2) superintendents accepted the role of leaders of reform; (3) change efforts took a systems approach; (4) there was an emphasis on curriculum and instruction; (5) resources were shifted to support improvement efforts; (6) principals and teachers were held accountable for student improvement; (7) research data were used to inform decisions; (8) more time was allotted for teacher and staff collaboration; (9) professional development of staff was used to support instructional improvement; and (10) the central office provided support for school-based efforts. Although intentionally research based, the report is intended to act as a guide to action. (Contains 29 references.) (WFA)