This report assesses the relative effectiveness of primarily voluntary and primarily mandatory desegregation plans in a sub-sample of 20 school districts, 9 of which are magnet-voluntary plans and 11 of which are magnet-mandatory plans. The major conclusions of this report are the following: (1) voluntary desegregation plans work; (2) dismantling mandatory plans and replacing them with comprehensive magnet-voluntary plans does not necessarily resegregate a school system; and (3) mandatory desegregation plans are not failures. Two school factors that are consistently important in predicting a magnet school's success are location and curriculum. The report provides the following information: (1) a review of research on white flight and the effectiveness of alternative desegregation plans; (2) the goals of a school desegregation plan; (3) the relative effectiveness of different magnet school programs; (4) the relative effectiveness of alternative desegregation plans (voluntary versus mandatory); (5) national desegregation trends from the 1960s through 1984; and (6) report findings and policy recommendations. Included are appendices with pertinent statistics on student demographics and school racial balance, and a bibliography. (PS)