School bullying is a serious problem worldwide, but little is known about how teacher interventions influence the adoption of bullying-related student roles. This study surveyed 750 early adolescents (50.5% female; average age: 12.9 years, SD = 0.4) from 39 classrooms in two waves, six months apart. Peer ratings of classmates were used to categorize students to five different bullying-related roles (criterion: >1 SD): bully, victim, bully-victim, defender, and non-participant. Student ratings of teachers were used to obtain class-level measures of teacher interventions: non-intervention, disciplinary sanctions, group discussion, and mediation/victim support. Controlling for student- and class-level background variables, two multilevel multinomial logistic regression analyses were computed to predict students' bullying-related roles at wave 2. In the static model, predictors were teacher interventions at wave 1, and in the dynamic model, predictors were teacher intervention changes across time. The static model showed that disciplinary sanctions reduced the likelihood of being a bully or victim, and group discussion raised the likelihood of being a defender. Mediation/victim support raised the likelihood of being a bully. The dynamic model complemented these results by indicating that increases in group discussion across time raised the likelihood of being a defender, whereas increases in non-intervention across time raised the likelihood of being a victim and reduced the likelihood of being a defender. These results show that teacher interventions have distinct effects on students' adoption of bullying-related roles and could help to better target intervention strategies. The findings carry practical implications for the professional training of prospective and current teachers.
