Marshall Medoff and Christopher Dennis identify some errors in National Abortion Rights Action League's (NARAL) data on the effective start dates of various state-level antiabortion laws. However, they misunderstand the purpose of my 2011 State Politics and Policy Quarterly article which was to measure the impact of a range of antiabortion laws—not analyze competing theories as to why the abortion rate has fallen in the United States. Furthermore, their analysis contains a number of critical measurement, and methodological and estimation errors. When these errors are corrected, the empirical results add to the substantial body of peer-reviewed research which finds that public funding restrictions, parental involvement laws, and properly designed informed consent laws all reduce the incidence of abortion.

The authors examine the impact of political party control of government on the restrictiveness of a U.S. state's abortion policy, measured by the enactment of a parental involvement law. The empirical results show that (1) institutional control of a state's legislative and executive branches of government by the Republican Party increases the likelihood a state will enact a parental involvement law, while Democratic Party control decreases this likelihood; (2) the more conservative state public opinion is on abortion rights, the more likely a state is to enact a parental involvement law; (3) public anti-abortion attitudes do not act as a moderating force on the link between political party control and the enactment of a parental involvement law; and (4) the impact of political party control on the enactment of a parental involvement law has grown larger over time.

Much of the academic literature that analyzes U.S. state-level restrictions on abortion focuses on parental involvement laws and the extent to which abortion is publicly funded through Medicaid. However, one shortcoming common to all of these studies is that they fail to analyze informed consent laws and other types of anti-abortion legislation that received constitutional protection through the U.S. Supreme Court's decision in Planned Parenthood of Southeastern Pennsylvania v. Casey (1992). In this study, a series of regressions on a comprehensive time series cross-sectional data set provides evidence that several types of state-level anti-abortion legislation result in statistically significant declines in both the abortion rate and the abortion ratio. Furthermore, a series of natural experiments provide further evidence that abortion restrictions are correlated with reductions in the incidence of abortion.