RESUMO
Sexual offences by multiple perpetrators are more violent and involve more severe forms of sexual violation than those perpetrated by a lone offender. Often a clear leader exists within these groups. Questions have been raised as to the relative risk of reoffending and the potentially differing criminogenic needs of leaders and followers. However, a recent study comparing leaders and followers in juvenile multiple perpetrator rapes (t'Hart-Kerkhoffs et al., 2011) failed to find some of the expected differences. It was proposed that this might be due, in part, to the way leaders and followers were classified in the study. Before work can progress in this area, it is important to devise reliable and valid means of identifying leaders and followers in multiple perpetrator rape. This article reports on a study which investigated the utility of two different methods of identifying leadership. The Scale of Influence (Porter & Alison, 2001) was applied to a sample of 256 offenders responsible for 95 multiple perpetrator rapes from the United Kingdom. Following this, the relative number of directives uttered by offenders was used to designate leadership. In 66% of the offences sampled, a leader was designated using the number of directives uttered compared with 80% when using the Scale of Influence. When combining both measures to form a composite measure of leadership, this percentage increased to 89%. Classifications of offenders as leaders, followers, and neither, according to the Scale of Influence, the count of directives, and the composite measure, were compared with classifications made by a practitioner to assess their concordance. The composite measure showed the greatest agreement with practitioner opinion. These findings suggest that the Scale of Influence could be developed to take account of other ways that leadership is displayed during multiple perpetrator rapes.