Abstract：
BACKGROUND: Gun buyback programmes have been popular in the USA since the 1970s. Studies show that they have no effect on citywide gun crime rates, but more microlevel examinations around gun buyback locations have not been conducted. This study tests for local effects of 34 Philadelphia, PA buyback events at 30 locations between 2019 and 2021.
METHODS: We analysed all gun-related crime events and gun-related calls for service attended by the police from 2019 to 2021. Multilevel models with an autoregressive residual structure were estimated on weekly gun crime and call event intensity (inverse distance weighted) totals across a range of distances (4000-8000 feet). Impacts of a gun buyback event were estimated for 1-4 weeks postevent.
RESULTS: Statistically significant weekly increases in gun event intensity are associated with seasonality and after the murder of George Floyd. Gun event intensity was not significantly affected by gun buybacks. Across 20 sensitivity tests of different distances and time periods (4000-8000 feet and between 1 and 4 weeks), gun buybacks were not statistically associated with any localised reduction in the intensity of gun crimes and calls.
CONCLUSIONS: Extant research has failed to uncover any effect of gun buybacks on citywide gun crime rates. The current results now contribute a lack of evidence at the local level to this literature. While gun buybacks remain popular with politicians and the public, this study adds to the ongoing question of whether buyback funds could be better spent more effectively.
METHODS: We analysed all gun-related crime events and gun-related calls for service attended by the police from 2019 to 2021. Multilevel models with an autoregressive residual structure were estimated on weekly gun crime and call event intensity (inverse distance weighted) totals across a range of distances (4000-8000 feet). Impacts of a gun buyback event were estimated for 1-4 weeks postevent.
RESULTS: Statistically significant weekly increases in gun event intensity are associated with seasonality and after the murder of George Floyd. Gun event intensity was not significantly affected by gun buybacks. Across 20 sensitivity tests of different distances and time periods (4000-8000 feet and between 1 and 4 weeks), gun buybacks were not statistically associated with any localised reduction in the intensity of gun crimes and calls.
CONCLUSIONS: Extant research has failed to uncover any effect of gun buybacks on citywide gun crime rates. The current results now contribute a lack of evidence at the local level to this literature. While gun buybacks remain popular with politicians and the public, this study adds to the ongoing question of whether buyback funds could be better spent more effectively.
摘要：
背景：枪支回购计划自1970年代以来在美国很受欢迎。研究表明，它们对全市枪支犯罪率没有影响，但是还没有围绕枪支回购地点进行更多的微观检查。这项研究测试了费城34的局部影响，2019年至2021年之间在30个地点举行的PA回购活动。
方法：我们分析了2019年至2021年所有与枪支有关的犯罪事件和与枪支有关的警察服务电话。在一系列距离（4000-8000英尺）的每周枪支犯罪和呼叫事件强度（距离加权倒数）总计上，估计了具有自回归残差结构的多级模型。枪支回购事件的影响估计要推迟1-4周。
结果：枪支事件强度的每周统计显着增加与季节性和乔治·弗洛伊德被谋杀后有关。枪支事件强度并未受到枪支回购的显着影响。在不同距离和时间段（4000-8000英尺，1至4周）的20项敏感性测试中，在统计上，枪支回购与枪支犯罪和电话的局部减少没有任何关联。
结论：现有研究未能发现枪支回购对全市枪支犯罪率的任何影响。目前的结果现在在地方层面上对该文献缺乏证据。虽然枪支回购在政客和公众中仍然很受欢迎，这项研究增加了一个持续存在的问题，即回购资金是否可以更有效地使用。
方法：我们分析了2019年至2021年所有与枪支有关的犯罪事件和与枪支有关的警察服务电话。在一系列距离（4000-8000英尺）的每周枪支犯罪和呼叫事件强度（距离加权倒数）总计上，估计了具有自回归残差结构的多级模型。枪支回购事件的影响估计要推迟1-4周。
结果：枪支事件强度的每周统计显着增加与季节性和乔治·弗洛伊德被谋杀后有关。枪支事件强度并未受到枪支回购的显着影响。在不同距离和时间段（4000-8000英尺，1至4周）的20项敏感性测试中，在统计上，枪支回购与枪支犯罪和电话的局部减少没有任何关联。
结论：现有研究未能发现枪支回购对全市枪支犯罪率的任何影响。目前的结果现在在地方层面上对该文献缺乏证据。虽然枪支回购在政客和公众中仍然很受欢迎，这项研究增加了一个持续存在的问题，即回购资金是否可以更有效地使用。
