Volume 14, 2009
Michael J. New
Using Natural Experiments To Analyze the Impact of State Legislation on the Incidence of Abortion
A number of academic studies find that various types of state level pro-life legislation reduce the incidence of abortion. However, in these states, it is possible that changes in values and mores, and not the legislation itself, might be responsible for these abortion declines. Indeed, since the enactment of pro-life legislation is not a random occurrence, the analysis of these laws might be biased by what social scientists call “endogeneity problems.” In this study, I address these endogeneity problems through a series of natural experiments. I compare abortion trends in states that enacted pro-life legislation to abortion trends in states where pro-life laws were passed, but later nullified by a judge. All states passing pro-life laws should have experienced similar changes in values, however, the policy changed only in those states where the law took effect. Overall, the results contribute to the body of academic literature which finds that pro-life legislation reduces state abortion rates.