Tuesday, 1 September 2009

The Effects of Abortion on Crime Rates

A study done by Chicago University’s scholars Steven Levitt (co-author of the book Freakonomics) and John J. Donohue III, can be used to explain with an example the strange links that sometimes exist in reality[1]. In the nineties the U.S. witnessed an incredible drop in crime rates (especially murder rates). The fall was incredible: close to 40%! Explanations of every kind started being given by the media and various experts. It was because of the increasing use of incarceration some were saying. It is because of the increase of the number of police officers! It is because of better policing strategies! It is because of better economic conditions! And so on and so forth.

Though, the study found that the above advocated causes were only (a minor) part of the truth. They had played a role of course, but they could not have been the only reasons of the sharp decline in criminality. Levitt & Donohue got out with another explanation. It was also because of 1973 law (Roe v. Wade) that had legalized abortion! (why the hell?! One may ask...) In the paper they write: “States with high abortion rates in the 1970s and 1980s experienced greater crime reductions in the 1990s. [...] Legalized abortion appears to account for as much as 50 percent of the recent drop in crime.”[2] The reason, in a few words, is that unwanted children are more likely to grow up in an difficult environment (e.g.: abandoned teenager mothers, economically disadvantaged families, etc...). And “Decades of studies have shown that a child born into an adverse family environment is far more likely than other children to become a criminal”.[3] Interesting findings!

Obviously someone opposed to the findings of the study (maybe for political views on the matter or maybe for more scientific reasons regarding the method[4]). But I don’t care here. I just wanted to bring an interesting example to show how sometimes causes of phenomena are hidden (e.g.: delayed in time; mixed with other, more evident, causes; etc...) and that conventional wisdom cannot always explain it.

[1] You can find the study at the following link : http://pricetheory.uchicago.edu/levitt/Papers/DonohueLevittTheImpactOfLegalized2001.pdf

If you don’t want to read boring academic stuff, the same explanations can be found in the book Freakonomics.

[2] Levitt, S. & Donohue, J. J. (2001). The Impact of Legalized Abortion on Crime. Quarterly Journal of Economics. Vol. CXVI, Issue 2. Pg. 379-420.

[3] Levitt, S. D & Dubner, S. J.(2005) Freakonomics. Harper Collins Publishers. New York. Pg.4.

[4] After some critics from other scholars a measurement error was acknowledged by Levitt & Donohue. Anyway, after reviewing the study they confirmed their previous findings.