Analyzes 6th grade reading achievement in 20 minority schools (predominantly black or Mexican American) in the Los Angeles Unified School District (LAUSD). All 20 displayed large or consistent percentile-point gains on the CTBS reading examination between 1972 and 1975. Background factors (such as socioeconomic status, health, ethnicity, and attendance) and earlier test scores accounted for the largest part of variation in scores. School and classroom factors found significant were teacher training in adapting varied materials to individual needs; teachers who felt efficacious; orderly classrooms; frequent parent-teacher contact; teacher flexibility in modifying instructional approaches; and frequent informal consultations among teachers in implementing reading programs. The study supports the continuation of the LAUSD program, which features school autonomy and teacher flexibility.