Objective

Third-party policing (TPP) refers to police efforts to persuade or coerce third parties to take some responsibility for crime control and prevention. The Yakuza Exclusion Ordinances (YEOs) of Japan aim to combat organized crime syndicates—the Yakuza. Consistent with the principles of TPP, the YEOs prohibit third parties (i.e., non-yakuza individuals) from providing any benefit to the yakuza. We argue that the effectiveness of the YEOs may depend on the strategic relationship among yakuza syndicates, where yakuza syndicates choose their power strategically to gain advantages over competition among rival yakuza syndicates.

Methods

We use unique data on the yakuza and construct a regional concentration index of yakuza syndicates. Exploiting prefecture-level variation in the YEOs’ enactment dates, we apply a difference-in-differences approach, while allowing for heterogeneity of the YEOs’ effect by the concentration of yakuza syndicates.

Results

The YEOs decrease the number of yakuza members and the effect of YEOs is greater in regions with lower concentration levels of yakuza syndicates. Given that yakuza members decrease by about 30% during the period of our study, our estimates suggest that the YEOs on average contribute to about 20% of a recent reduction of yakuza members.

Conclusions

The YEOs are related to TPP strategies that rely on coercive techniques, and thus our results suggest the effectiveness of TPP strategies against organized crime. Furthermore, the heterogeneity of the YEOs’ effect suggests the effectiveness of enforcement policies that intensively target regions with lower concentration of organized crime.

中文翻译：

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针对有组织犯罪的第三方警务方法：对黑帮排除条例的评估

客观的

第三方警务（TPP）是指警方说服或胁迫第三方承担一定的犯罪控制和预防责任的努力。日本的黑帮排除条例 (YEOs) 旨在打击有组织的犯罪集团——黑帮。与 TPP 的原则一致，YEO 禁止第三方（即非黑帮个人）向黑帮提供任何利益。我们认为，YEO 的有效性可能取决于黑帮集团之间的战略关系，黑帮集团战略性地选择他们的权力，以在敌对黑帮集团之间的竞争中获得优势。

方法

我们使用关于黑帮的独特数据并构建黑帮集团的区域集中指数。利用 YEOs 颁布日期的县级差异，我们应用了差异中的差异方法，同时允许 YEOs 影响的异质性因 yakuza 辛迪加的浓度而异。

结果

YEO 减少了黑帮成员的数量，而 YEO 的影响在黑帮集团集中度较低的地区更大。鉴于在我们的研究期间黑帮成员减少了约 30%，我们的估计表明，在最近黑帮成员的减少中，YEO 平均贡献了约 20%。

结论

YEO 与依赖强制技术的 TPP 战略有关，因此我们的结果表明 TPP 战略对打击有组织犯罪的有效性。此外，YEO 影响的异质性表明，集中针对有组织犯罪集中度较低的地区的执法政策是有效的。