Results from the evaluation of a large-scale educational intervention designed to prevent school disruption suggest that altering the school organization is a more effective approach to delinquency prevention than treating individuals. Data for this comparison came from the evaluation of a school-based delinquency prevention program, Project PATHE, that operated in seven Charleston, South Carolina, public secondary schools between 1980 and 1983. Two other schools are used for comparison purposes. The following steps, taken together, were found to reduce school disruption: involving the school staff, students, and community members in planning and implementing change; using information to identify weaknesses and focusing resources on those weaknesses; retraining school staff; and making changes in the curriculum and discipline procedures in the school. Using roughly the same level of resources to provide what, for a typical school system, is intensive tutoring and counseling services of high quality appears not to have reduced delinquency or its risk factors. Appended are 3 data tables and 11 project reference. (MLF)