The Emergence of Crack Cocaine and the Rise in Urban Crime Rates
利用27个大都市区的FBI犯罪率数据和快克可卡因首次出现的时间信息，发现快克的出现显著推高了城市犯罪率；若无快克，1991年城市犯罪率峰值将降低约10%。
Despite widespread popular accounts that link crack cocaine to inner-city decay, little systematic research has analyzed how the emergence of crack affected urban crime. We study this question using FBI crime rates for 27 metropolitan areas and two sources of information on when crack first appeared in those cities. Using methods designed to control for unobserved differences among metropolitan areas, we find that the introduction of crack had substantial effects on crime. In the absence of crack cocaine, the 1991 peak in urban crime rates would have been approximately 10% lower, remaining below the previous peak levels of the early 1980s. © 2000 by the President and Fellows of Harvard College and the Massachusetts Institute of Technology