This blog is intended to go along with Population: An Introduction to Concepts and Issues, by John R. Weeks, published by Wadsworth Cengage Learning. The latest edition is the 11th (copyright 2012, although it actually came out in 2011), but this blog is meant to complement any edition of the book by showing the way in which demographic issues are regularly in the news. Note that the 12th edition is currently in production and will be out in 2015.

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Tuesday, May 24, 2011

Do Demographics Explain the Latest Drop in Crime Rates?

The Federal Bureau of Investigation has just issued its latest crime report and the New York Times reports that the data reveal a drop in crime in the US:
The number of violent crimes in the United States dropped significantly last year, to what appeared to be the lowest rate in nearly 40 years, a development that was considered puzzling partly because it ran counter to the prevailing expectation that crime would increase during a recession.
All of the experts interviewed for the story were baffled by this trend, and that immediately called to my mind the highly controversial theory put forth by Steven Levitt and Stephen Dubner in their very popular book Freakonomics. In Chapter 4 of that book they argue that:
In the early 1990s, just as the first cohort of children born after Roe v. Wade was hitting its late teen years—the years during which young men enter their criminal prime—the rate of crime began to fall. What this cohort was missing, of course, were the children who stood the greatest chance of becoming criminals. And the crime rate continued to fall as an entire generation came of age minus the children whose mothers had not wanted to bring a child into the world. Legalized abortion led to less unwantedness; unwantedness leads to high crime; legalized abortion, therefore, led to less crime.
The interesting thing about that theory is, of course, that it fits with the demographic idea that changing cohort size and characteristics make a difference in society. If we look back approximately twenty years ago from now, what demographic factors can we find that might help us explain a drop in crime? One possibility is the steep decline in teenage birth rates among all groups in American society. Birth rates among 15-17 year old girls were 45% lower in 2008 than in 1991 and 26% lower among 18-19 year olds. Since we can assume that a large fraction of babies to girls that age are unwanted, a drop in the birth rate to young mothers will, paraphrasing Levitt and Dubner's words, lead to less unwantedness; unwantedness leads to high crime; lower teen birth rates, therefore, lead to less crime. 
This conclusion will have to wait for more detailed investigation, but in the meantime, some NFL football players are concerned that the crime rate will go up if they aren't allowed to play this fall...

1 comment:

  1. At face value, it seems odd to compare crime rates and abortion. However, when you look at those who commit crimes, you often see a history of abuse/neglect in their childhood. Parents who do not want the children they have will abuse or neglect them. Therefore, providing a way for them not to have those children may reduce the population of criminals in the future. Subsequently, legal abortion may reduce crime when those potentially unwanted children would be entering their teenage years, when criminal activity usually begins. In the case of Roe v. Wade, states that had legalized abortion prior to the landmark case saw a significant drop in violent crime before any other states. This appears to be indisputable proof that unwanted children lead to abuse, which lead to violent crime. Access to legal abortions may reduce violent crime within 15 years.

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