This report presents the findings and recommendations of an examination of the implementation of a major form of school-based management (SBM). It is based on case studies of the science and mathematics departments of 10 high schools and 9 middle or junior high schools in 12 school systems, almost all of which are urban school districts. The study found that implementation often falls short of the ideal. It did not find dramatic changes resulting from SBM. However, those schools and faculty members that took advantage of their added flexibility under SBM were able to achieve numerous small-scale improvements. The report provides a series of recommendations for school districts and individual schools to increase the likelihood of successful implementation of decentralization efforts such as SBM. The findings and recommendations cover such issues as (1) the extent of decentralization of budgeting expenditure and personnel decisions, (2) the role of site councils and department heads, and (3) communication and training needs. Appendixes list participating schools and districts and contain a literature review. (Contains 117 references.) (Author/SLD)