Group treatment of reactive aggressors by social workers in a Hong Kong school setting: a two-year longitudinal study adopting quantitative and qualitative approaches

The most widely adopted school bullying interventions include mediation, support groups, and the restorative justice, strengthening the victim, shared concern and traditional disciplinary approaches. The schoolchildren involved in these interventions are classified simply as aggressors or victims. This article aims to expand social workers' understanding of aggression and ways of treating particular types of reactive aggressors using the Social Information Processing model. It reports the results of a two-year longitudinal study of sixty-six eleven-to-sixteen-year-old high-risk reactive aggressors randomly assigned to intervention groups administered by social workers in ten Hong Kong secondary schools. The study employs five checkpoints for an evaluation of effectiveness. The results of single-factor repeated-measures analysis show significant differences in participants' aggression levels at the different checkpoints, with post-hoc analysis indicating a significant decline in these levels at the three-month and one- and two-year follow-ups relative to the pre- and post-tests. Polynomial contrasts reveal a significant linear trend for aggressive behaviour, qualified by the significant higher-order trend for the different aggression subscales, which suggests a possible curvilinear treatment effect. The study's qualitative results provide strong evidence-based support for the effectiveness of the treatment programme and show the need to differentiate amongst specific aggression types in interventions.