Objectives

This study assesses the effects of a Group Violence Intervention (GVI) implementation in Philadelphia on group member-involved (GMI) firearm violence. Because the implementation began in August 2020 during the COVID-19 pandemic, public health restrictions necessitated relying on individualized Mobile Call-In Team (MCIT) custom notifications, rather than large-scale call-in meetings, as the primary implementation method.

Methods

During the January 2020–May 2022 study period, not all at-risk group-units received GVI treatment at the same time. Likewise, not all census tracts received GVI treatment at the same time. Given this variation in treatment initiation, a quasi-experimental stepped wedge design assessed the effect of GVI treatment on GMI shootings on the dimensions of both group and place. Estimates were calculated using Poisson regression. The effects of treatment dosage were also assessed.

Results

A group-unit, post-treatment relative to pre-treatment, experienced, on average, a significant 38.6% reduction in shootings per week. Where a census tract received between 4 and 7 doses relative to 0 doses (pre-treatment), there was a significant 51.0% reduction in GMI shootings per week.

Conclusions

A GVI implementation through custom notifications appears to maintain the effectiveness of GVI. Future research should assess the role of GVI components, including both enforcement actions and social services, as mechanisms for GVI effectiveness in a custom notification-based implementation.

中文翻译：

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评估群体暴力干预对费城枪支暴力的影响

目标

本研究评估了费城实施的群体暴力干预 (GVI) 对群体成员参与 (GMI) 枪支暴力的影响。由于该实施是在 2020 年 8 月 COVID-19 大流行期间开始的，因此公共卫生限制需要依靠个性化的移动呼入团队 (MCIT) 自定义通知，而不是大规模的呼入会议作为主要实施方法。

方法

在 2020 年 1 月至 2022 年 5 月研究期间，并非所有高危人群单位同时接受 GVI 治疗。同样，并非所有人口普查区同时接受 GVI 处理。鉴于治疗开始的这种变化，准实验阶梯楔形设计评估了 GVI 治疗对 GMI 枪击事件在群体和地点方面的影响。使用泊松回归计算估计值。还评估了治疗剂量的影响。

结果

与治疗前相比，治疗后的团体单位每周枪击事件平均显着减少 38.6%。当人口普查区接受 4 至 7 剂疫苗（相对于 0 剂疫苗（治疗前））时，每周 GMI 枪击事件显着减少 51.0%。

结论

通过自定义通知实施 GVI 似乎可以保持 GVI 的有效性。未来的研究应评估 GVI 组成部分（包括执法行动和社会服务）的作用，作为基于自定义通知的实施中 GVI 有效性的机制。