Drugs on the Web, Crime in the Streets. The Impact of Shutdowns of Dark Net Marketplaces on Street Crime
研究暗网市场关闭是否导致街头毒品交易增加，发现关闭后大麻相关犯罪短期上升约5%，但18天内恢复，对其他犯罪无显著影响。
The Dark Net has changed the way drugs are traded globally by shifting trade away from the streets and onto the web. In this paper, I study whether the shutdown of Dark Net marketplaces has an impact on the amount of drugs traded in the streets and on crimes that are normally associated to street drug dealing. To identify a causal effect, I use daily data from the US and exploit unexpected shutdowns of large online drug trading platforms. In a regression discontinuity design, I compare crime levels in days after the shutdowns to those immediately preceding them. I find that shutting down Dark Net marketplaces leads to a significant increase in drug trade in the streets. However, the effect is short-lived. In the days immediately following shutdowns, marijuana-related crimes increase by around five percent but revert to pre-shutdown levels within eighteen days. I find no impact of shutdowns of Dark Net marketplaces on thefts, assaults, homicides and prostitution.