Did Legalized Abortion Lower Crime?

This paper examines the relationship between the legalization of abortion and subsequent decreases in crime. In a current study, researchers estimate that the legalization of abortion explains over half of the recent decline in national crime rates. The association is identified by correlating changes in crime with changes in the abortion ratio weighted by the proportion of the criminal population exposed to legalized abortion. In this paper, I use an alternative identification strategy. I analyze changes in homicide and arrest rates among teens and young adults born before and after 1970 in states that legalized abortion prior to Roe v. Wade. I compare these changes with variation in homicide and arrest rates among cohorts from the same period but who were unexposed to legalized abortion. I find little evidence to support the claim that legalized abortion caused the reduction in crime. I conclude that the association between abortion and crime is not causal, but most likely the result of confounding from unmeasured period effects such as changes in crack cocaine use and its spillover effects.