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Evaluation of the Olweus Bullying Prevention Program in US Urban Middle Schools Using a Multiple Baseline Experimental Design

NCJ Number
Prevention Science Dated: April 26, 2021
Terri N. Sullivan; Albert D. Farrell; Kevin S. Sutherland; Kathryn L. Behrhorst; Rachel C. Garthe; Anne Greene
Date Published
April 2021
13 pages

This article reports the findings and methodology of an evaluation of the impact of the Olweus Bullying Prevention Program (OBPP), which involved an 8-year study in urban middle schools that served primarily African American students living in low-income areas.


Participants were 2,755 students and 242 teachers. The evaluation of the OBPP used a multiple-baseline experimental design in which the order and intervention start time were randomly assigned for each school. The frequency of bullying behaviors and experiences measured included physical, relational, and verbal aggression and victimization. These were determined by using teacher ratings of student behavior and student-reported data; cyber aggression, victimization, and school climate were measured by using student-reported data. Teacher ratings of student behavior indicated significant main effects across all subtypes of aggression and victimization, with some variability in the timing of effects. The pattern of findings showed delayed intervention effects for boys and a weaker impact of the OBPP on 6th graders. Main effects were found for student-reported cyber aggression and victimization; relational aggression; and a composite of physical, verbal, and relational victimization. Decreases in victimization emerged in the first or second year of intervention, and reductions in aggression emerged during the third year. Across all findings, once intervention effects emerged, they remained significant in subsequent intervention years. The OBPP resulted in significant decreases in student-reported and teacher-reported aggression and victimization; however, this intervention had limited impact on general areas of school climate, including teacher support, positive peer interactions, and school safety. Overall, the findings have important prevention and research implications. (publisher abstract modified)