The purpose of this study was to evaluate the effectiveness of Safer Bars, an intervention to reduce aggression in bars. A total of 734 pre - post-intervention observations were conducted by trained observers on Friday and Saturday nights between midnight and 2 a.m. in 18 large capacity ( > 300) Toronto bars and clubs assigned randomly to receive the intervention (69% participation rate of the 26 assigned) and 12 control bars. As part of the intervention, owners/managers completed the risk assessment workbook to identify ways of reducing environmental risks, and 373 staff and owners/managers (84% participation rate) attended a 3-hour training session focused on preventing escalation of aggression, working as a team and resolving problem situations safely. The main outcome measures were rates of severe aggression (e.g. punching, kicking) and moderate physical aggression (e.g. shoving, grappling). Hierarchical linear modelling (HLM) comparing pre - post aggression for intervention versus control bars indicated a significant effect of the intervention in reducing severe and moderate aggression. This effect was moderated by turnover of managers and door/security staff with higher post-intervention aggression associated with higher turnover in the intervention bars. The findings indicate the potential for a stand-alone relatively brief intervention to reduce severe and moderate physical aggression in bars.

Findings of this study indicate differences in the extent to which college settings are associated with student drinking levels before, during and after related events, and may have implications for intervention strategies targeting different types of settings.