Diagnostic classification of schools into types according to several school characteristics may be helpful in pinpointing causes for student disruption. Responses to questionnaires administered to principals, teachers, and students in over 600 junior and senior high schools showed that a common group of characteristics was shared by many central city schools and another group by suburban schools. Those characteristics clustered under the term "urban disorganization" correlated with higher rates of school disruption than did the characteristics grouped under the term "academic suburbanism." School characteristics measured in the study included community characteristics (location, employment levels, poverty or affluence, education levels, crime rate, and so on), school facility conditions, teacher and student characteristics, school organization types, parental involvement, and the nature of the formal and informal relationships among teachers, students, and administrators as perceived by them. While the data collection methods were not completely reliable, the broad generalizations supported by the information gathered indicated that further, more controlled research could lead to clearer, more detailed results. (PGD)