Objectives

A high number of street dealers operate in the Red Light District in Amsterdam, The Netherlands. To displace the dealers, the Municipality of Amsterdam installed text-based light projections in a street attracting a high number of dealers.

Methods

To evaluate the intervention, we did a pre-post analysis of video footage from two CCTV cameras located in the street. In total, we analyzed 765 one-minute segments of footage from before and after the implementation.

Results

The implementation was followed by a four percentage point reduction in street dealers. However, the estimated effect shows fragileness with wide confidence intervals and a p-value just below 0.05, and a Bayesian robustness analysis suggests that the intervention was not associated with the outcome.

Conclusions

Analyzing CCTV-footage offers a unique avenue for evaluating small scale interventions in open-air drug markets. While we observed a decrease in the presence of dealers, the intervention still needs further validation.

中文翻译：

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“从街头毒贩那里购买毒品是违法的”——一项基于视频的事前研究，旨在将毒贩赶出阿姆斯特丹露天毒品市场

目标

荷兰阿姆斯特丹红灯区有大量街头毒贩。为了取代经销商，阿姆斯特丹市政府在一条吸引大量经销商的街道上安装了基于文本的灯光投影。

方法

为了评估干预措施，我们对街道上两个闭路电视摄像机的视频片段进行了事前分析。我们总共分析了实施前后的 765 个一分钟片段。

结果

实施后，街头毒贩数量减少了四个百分点。然而，估计的效果显示出脆弱性，置信区间较宽，p值略低于 0.05，贝叶斯稳健性分析表明干预与结果无关。

结论

分析闭路电视录像为评估露天毒品市场的小规模干预提供了独特的途径。虽然我们观察到经销商数量有所减少，但干预措施仍需要进一步验证。