Although only a few dozen school systems have formally embraced site-based management, thousands of districts across the country are experimenting with it in some form. The study described in this report attempts to distill the experience of pioneering school systems, so that citizens and educators in other localities can benefit from it. During the 1989-90 and 1990-91 school years, a RAND research team studied five major urban and suburban school systems that had adopted site-based management: Columbus, Ohio; Dade County, Florida; Edmonton, Alberta (Canada); Jefferson County (Louisville), Kentucky; and Prince William County, Virginia. Newspaper and scholarly accounts of site-based management in other communities were also considered. The report draws five major conclusions: (1) though site-based management focuses on individual schools, it is really a reform of the entire school system; (2) site-based management will lead to real changes at the school level only if it is a school system's basic reform strategy; (3) site-based schools are likely to evolve over time and to develop distinctive characters, goals, and operating styles; (4) a system of distinctive, site-based schools requires a rethinking of accountability; and (5) the ultimate accountability mechanism for a system of distinctive site-based schools is parental choice. These findings have specific implications for the entire school community. An appendix provides an overview of the five districts studied. (MLH)