The school effectiveness movement stresses a safe and orderly learning environment for students. Concern for students' and parents' legal rights, coupled with recent criticism of school practices regarding corporal punishment, suspension, and expulsion, has spawned research into theoretical, practical, and legal implications related to pupil behavior and discipline. This study illustrates the need for reliable information from which informed decisions about student discipline can be made. A system for collecting and managing districtwide discipline data is described. Aided by many tables and charts, this paper summarizes results from the first two years of a longitudinal study conducted in Jackson (Mississippi) public schools during the 1984-85 and 1985-86 school years. A standardized form was filled out for each instance of disciplinary action. Findings indicate that (1) disciplinary action frequency varied among schools and grade levels; (2) most offenses involved minor fighting incidents, classroom disruption, and insubordination; (3) most offenses occurred in classrooms, hallways, or on school grounds; (4) only a few students were multiple offenders; (5) district costs for suspensions were considerable; and (6) the frequency and number of offenses decreased the second year. The district should create a more unified discipline policy, continue special teacher training in behavior management, and develop special programs for potential offenders and suspended students. Included are seven tables, two charts, and an appendix comprised of three disciplinary action forms. (MLH)