We are grateful to Foote and Goetz for noting that the final table of Donohue and Levitt (Quarterly Journal of Economics, 116 (2001), 379–420) inadvertently omitted state-year interactions. Correcting our mistake does not alter the sign or statistical significance of our estimates, although it does reduce their magnitude. Using a more carefully constructed measure of abortion that better links birth cohorts to abortion exposure (by using abortion data by state of residence rather than of occurrence, by adjusting for cross-state mobility, and by more precisely estimating birth years from age of arrest data), we present new evidence that abortion legalization reduces crime through both a cohort-size and a selection effect.

Street gangs have a long history in American cities (Thrasher 1927). Until recently, gangs were organized primarily as social peer groups. Any economic activities were of secondary importance (Suttles 1968, Klein 1995). The last two decades, however, have given rise to a dramatic transformation in street gangs, or what Taylor (1990) terms their "corporatization."

In this article, we analyze the 1920s Ku Klux Klan, those who joined it, and its social and political impact by combining a wide range of archival data sources with data from the 1920 and 1930 U.S censuses. We find that individuals who joined the Klan in some cities were more educated and more likely to hold professional jobs than the typical American. Surprisingly, we find little evidence that the Klan had an effect on black or foreign-born residential mobility or vote totals. Rather than a terrorist organization, the 1920s Klan is best described as social organization with a very successful multilevel marketing structure fueled by an army of highly incentivized sales agents selling hatred, religious intolerance, and fraternity in a time and place where there was tremendous demand.