There is a need to increase understanding of the effectiveness of bystander programmes targeting gender-based violence in the United Kingdom. There is also a need to utilise a robust theoretical models of decision-making while doing so. Changes were examined in bystanders’ attitudes, beliefs, motivations towards intervening, and intervention behavior in situations of gender-based violence. To achieve this, a quantitative examination of Mentors in Violence Prevention was conducted. There were 1396 participants (50% female, 50% male) who were aged 11 to 14 years old (M = 12.25, SD = 0.84) attending high school at the first time point. Participants were attending 17 schools (53% Mentors in Violence Prevention and 47% control) in Scotland. Outcome variables were assessed approximately one year apart using questionnaires. Multilevel linear regressions revealed that Mentors in Violence Prevention did not change outcomes reflecting bystanders’ attitudes, beliefs, motivations towards intervening, or intervention behavior in gender-based violence. Discrepancies between the current findings and those of other evaluations may be due to other studies including small numbers of schools that may be more motivated to implement the program. This study also identified two key issues that need to be addressed at stakeholder level before concluding that Mentors in Violence Prevention is ineffective at targeting gender-based violence. That the program has moved towards a more gender-neutral approach in the United Kingdom could explain the null results of this study. Furthermore, the current findings could be attributed to a failure to adequately address the theoretical model underpinning the program in practice.

有必要加深对英国针对性别暴力的旁观者计划有效性的了解。在此过程中还需要利用强大的决策理论模型。研究了旁观者在基于性别的暴力情况下的态度、信仰、干预动机和干预行为的变化。为了实现这一目标，对暴力预防导师进行了定量检查。有 1396 名参与者（50% 女性，50% 男性）年龄在 11 至 14 岁（M = 12.25，SD = 0.84）在第一个时间点上高中。参与者就读于苏格兰的 17 所学校（53% 为暴力预防导师，47% 为控制学校）。使用调查问卷对结果变量进行大约一年的评估。多级线性回归显示，暴力预防导师并没有改变反映旁观者干预性别暴力的态度、信仰、动机或干预行为的结果。目前的调查结果与其他评估结果之间的差异可能是由于其他研究造成的，其中包括少数可能更有动力实施该计划的学校。这项研究还确定了利益相关者层面需要解决的两个关键问题，然后才得出暴力预防导师在打击性别暴力方面无效的结论。英国的该计划已转向更加性别中立的方法，这可以解释这项研究的无效结果。此外，目前的发现可能归因于未能在实践中充分解决支撑该计划的理论模型。