The Impact of Legalized Abortion on Crime
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"The Impact of Legalized Abortion on Crime" is a controversial paper by John J. Donohue III of Yale University and Steven Levitt of University of Chicago that argues that the legalization of abortion in the early 1970s contributed significantly to reductions in crime rates experienced in the 1990s. The paper, published in the Quarterly Journal of Economics in 2001, offers evidence that the falling United States crime rates of the 1990s were mostly caused by the legalization of abortion due to the Roe v. Wade court decision of 1973 .
"We offer evidence that legalized abortion has contributed significantly to recent crime reductions. Crime began to fall roughly eighteen years after abortion legalization. The five states that allowed abortion in 1970 experienced declines earlier than the rest of the nation, which legalized in 1973 with Roe v. Wade. States with high abortion rates in the 1970s and 1980s experienced greater crime reductions in the 1990s. In high abortion states, only arrests of those born after abortion legalization fall relative to low abortion states. Legalized abortion appears to account for as much as 50 percent of the recent drop in crime."
History of argument
The 1972 Rockefeller Commission on Population and the American Future is one of the better known early versions of this claim, but it was not the first. The Commission cited research purporting that the children of women denied an abortion "turned out to have been registered more often with psychiatric services, engaged in more antisocial and criminal behavior, and have been more dependent on public assistance." A 1966 study by Hans Forssman and Inga Thuwe was cited by the Rockefeller Commission and is probably the first serious empirical research on this topic. They studied the children of 188 women who were denied abortions from 1939 to 1941 at the hospital in Gothenburg, Sweden. They compared these "unwanted" children to another group – the next child born after each of the unwanted children at the hospital. The "unwanted" children were more likely to grow up in adverse conditions, such as having divorced parents or being raised in foster homes and were more likely to become delinquents and engaged in crime. Supreme Court Justice Blackmun opinion in Roe v. Wade also referenced the social and private problems "of bringing a child into a family already unable, psychologically and otherwise, to care for it." Levitt and Donohue revived discussion of this issue with their paper, "The Impact of Legalized Abortion on Crime."
In 1999, before the paper was published, a debate was held between magazine writer and Internet columnist Steve Sailer and Steven Levitt at Slate.com. (See this link for Levitt's opening, this link for Sailer's response, this link for Levitt's rebuttal, and this link for a final Sailer response.) Sailer argues that the end of the crack wars was more significant than abortion -- and that, contrary to what Levitt's thesis would suggest, "the murder rate for 1993's crop of 14- to 17-year-olds (who were born in the high-abortion years of 1975 to 1979) was a horrifying 3.6 times that of the kids who were 14 to 17 years old in 1984 (who were born in the pre-legalization years of 1966 to 1970)."
Lott and Whitley
In 2001, John Lott and John Whitley argued that Donohue and Levitt assume that states which completely legalized abortion had higher abortion rates than states where abortion was only legal under certain conditions (many states allowed abortion only under certain conditions prior to Roe) and that CDC statistics do not substantiate this claim. In addition, if abortion rates cause crime rates to fall, crime rates should start to fall among the youngest people first and then gradually be seen lowering the crime rate for older and older people. In fact, they argue, the murder rates first start to fall among the oldest criminals and then the next oldest criminals and so on until it last falls among the youngest individuals. Lott and Whitley argue that if Donohue and Levitt are right that 80 percent of the drop in murder rates during the 1990s is due solely to the legalization of abortion, their results should be seen in these graphs without anything being controlled for, and that in fact the opposite is true. In addition, Lott and Whitley pointed out that using arrest rate data to proxy crime rates is flawed because arrests for murder can take place many months or even years after the crime occurred. Lott and Whitley show that using the Supplemental Homicide Report, which links murder data for when the crime occurred with later arrest rate data, reverses Donohue and Levitt's regression results.
Ted Joyce made a number of arguments against the abortion and crime hypothesis in his 2004 paper "Did Legalized Abortion Lower Crime?". He claimed that legal abortions in the early 1970s were just replacing illegal abortions, that there was no measurable impact of abortion between 1985 and 1990, that cohorts born before 1973 had roughly the same crime rates as cohorts born after 1973 in the states where abortion was legalized in 1973, and that omitted variables are driving the results.
Donohue and Levitt respond to each point that Joyce makes in a reply paper and conclude that none of Joyce's arguments cast doubt on the original hypothesis presented in their 2001 paper. They also introduce an updated version of their dataset which had better measures of abortion (given to them by Stanley Henshaw of the Alan Guttmacher Institute after their initial paper was published).
Foote and Goetz
In November 2005, Federal Reserve Bank of Boston economists Christopher Foote and Christopher Goetz released a working paper pointing out a number of errors in the paper, including both coding errors, so Donohue and Levitt's study did not estimate the regressions that were claimed, and incorrectly using total arrest numbers rather than per-capita numbers, so reduction in crime were simply a consequence of lower population, not decreases in the crime rate. In particular, Foote and Goetz said that, despite their claims that they had done so, the 2001 Donohue and Levitt study failed to control for influences that varied within a state from year to year (such as the effect of crack-cocaine). Foote and Goetz also point out that Donohue and Levitt accidentally used the total number of arrests, not the arrest rate, to explain the murder rate. Using the total number of arrests does not establish the unwantedness mechanism Donohue and Levitt propose only that the total number of arrests has changed. After making these two corrections, Foote and Goetz interpreted their results as evidence that violent crime actually increases with more abortions and that property crime is unrelated to abortions. This study received press coverage in The Wall Street Journal and The Economist.
Donohue and Levitt admit the programming error made in the original version of the paper and then go on to address the two points that Foote and Goetz make. Donohue and Levitt contend that even though the Foote and Goetz analysis was doing what Donohue and Levitt claim that they were originally doing, the Foote and Goetz analysis produces heavy attenuation bias (the reason they find no statistical relationship between abortion and crime). To remedy this, Donohue and Levitt use the improved abortion measures (that Lott and Whitley originally used) and they make other changes that they now argue are necessary. But they continued to not use the Supplemental Homicide Data that linked the exact timing of the murder to later arrest rate data. Donohue and Levitt claim that with these new changes the results are smaller, but still statistically significant.
Rick Nevin suggests an alternative explanation for the correlation observed by Donohue and Levitt. His study, which included several other countries in addition to the United States, suggests that variations in estimated early-childhood blood lead levels (from exposure to leaded gasoline and paint) can better explain the variation in violent crime rates over the years. For example, it better explains why crime rates rose in the first place, and continued to rise in the UK (who continued to use leaded gasoline after the USA phased it out) even though abortion was legalized. It also explains why New York (especially NYC) and California (which legalized abortion before Roe) saw crime rates drop earlier than the rest of the nation, since they were also more proactive in reducing lead exposure. The theory is biologically plausible, given that lead is a known neurotoxin which has long been linked to impulsivity, delinquency, violence, and reduced IQ. However, neither Nevin's nor Donohue and Levitt's hypothesis can explain the differences in timing of the drops in crime between the US and Canada.
In Levitt's reply in his Freakonomics blog at the New York Times, he notes that while a 2007 study by Jessica Reyes also found that lead had a large effect on violent crime, the same study found that the effect of legalized abortion remained similar in magnitude to that in Levitt's study, and statistically and practically significant (albeit as a lesser factor), even after controlling for blood lead levels and several other possible confounders. Reyes: "This paper shows a significant and robust relationship between lead exposure in childhood and violent crime rates later in life. The estimates indicate that the reduction in lead exposure in the 1970s is responsible for a 56% drop in violent crime in the 1990s and will likely produce further declines in the future, up to a 70% drop in violent crime by the year 2020. The legalization of abortion, as identified by Donohue and Levitt, remains an important and significant factor. Thus, two major acts of government, the Clean Air Act and Roe v. Wade, neither intended to have any effect on crime, may have been the largest factors affecting violent crime trends at the turn of century." (p. 35). "By the year 2020, when the effects of the Clean Air Act and Roe v. Wade would be complete, violent crime could be as much as 70% lower than it would be if lead had remained in gasoline, and as much as 35-45% lower than it would be if abortion had never been legalized. At the same time, history suggests that other unknown factors would have increased crime by perhaps 3-5% per year." (p.33).
- "Full text of "The Impact of Legalized Abortion on Crime" in PDF.
- Rockefeller Commission on Population and the American Future
- Hans Forssman and Inga Thuwe, "One hundred and twenty children born after application for therapeutic abortion refused," Acta Psychiatrica Scandinavica, 1966, 71-78
- Roe v. Wade (No. 70-18) 314 F.Supp. 1217
- John R. Lott Jr. and John E. Whitley, "Abortion and Crime: Unwanted Children and Out-of-Wedlock Births", (2001) SSRN Yale Law & Economics Research Paper No. 254 working paper and Economic Inquiry, Vol. 45, No. 2, pp. 304-324, April 2007 published article.
- Abortion and crime: who should you believe?
- Ted Joyce, Did Legalized Abortion Lower Crime?, Journal of Human Resources, 2004, Vol. 39, No.1, pp. 1-28.
- "Further Evidence that Legalized Abortion Lowered Crime: A Reply to Joyce" Journal of Human Resources, 2004, 39(1), pp. 29-49.
- "Testing Economic Hypotheses with State-Level Data: A Comment on Donohue and Levitt (2001).", Christopher L. Foote and Christopher F. Goetz, Federal Reserve Bank of Boston Working Papers 05-15
- Foote, Christopher L.; Goetz, Christopher F. (February 2008). "The Impact of Legalized Abortion on Crime: Comment". Quarterly Journal of Economics 123 (1): 407–423. doi:10.1162/qjec.2008.123.1.407, originally published in Federal Reserve Bank of Boston Working Papers, 2005 Series, No. 05-15 as "Testing Economic Hypotheses with State-Level Data: A Comment on Donohue and Levitt (2001)" in November 2005.
- Jon E. Hilsenrath, 'Freakonomics' Abortion Research Is Faulted by a Pair of Economists The Wall Street Journal, November 28, 2005.
- Abortion, crime and econometrics The Economist, Dec 1st 2005.
- "Measurement Error, Legalized Abortion, the Decline in Crime: A Response to Foote and Goetz (2005)", Donohue and Levitt, 2006
- Research Links Lead Exposure, Criminal Activity, Washington Post, July 8, 2007
- Preschool blood lead levels correlate with later criminality, CrimeTimes, 2007
- http://www.icfi.com/publications/register/download-register.asp?pubid=116. Research Links Childhood Lead Exposure to Changes in Violent Crime Rates Throughout the 20th Century, Rick Nevin, ICF Consulting
- Freedomnomics: Why the Free Market Works and Other Half-Baked Theories Don't, Regnery Publishing; First Edition edition (June 4, 2007)
- Freakonomics - Rick Nevin
- http://www.bepress.com/bejeap/vol7/iss1/art51/ Reyes, Jessica Wolpaw (2007) "Environmental Policy as Social Policy? The Impact of Childhood Lead Exposure on Crime," The B.E. Journal of Economic Analysis & Policy: Vol. 7 : Iss. 1 (Contributions), Article 51. doi:10.2202/1935-1682.1796