Beginning around 2040, the US will experience a sudden jump in the crime rate, especially so in the red states.

How on Earth did I reach such a conclusion? In their 2005 bestseller, Freakonomics, Steven Dubner and Stephen Levitt famously analysed the inner workings of a crack gang, the truth about real-estate agents, the telltale grades of a cheating schoolteacher, and other fascinating and quirky sociological topics.

One of the most memorable chapters has to do with why the US experienced a dramatic reduction in all forms of crime in the mid-90s. Multiple possible causes are considered, but evidence shows the strong impact of an event that occurred 20 years earlier: the Roe v. Wade Supreme Court decision of 1973 legalizing abortion as a constitutional right.

This theory holds that children born of unwanted pregnancies are at the highest risk of committing crimes. When abortion became legal and widely available in the US, fewer unwanted pregnancies were carried to term, and the results of that effect were felt roughly 20 years later, when those aborted fetuses would have reached adulthood. They simply weren’t there to commit the crimes.

This video summarizes this theory:

You may or may not agree with the theoretical premise, however, statistical analysis supports this conclusion:

  • Five US states legalized abortion three years before the Roe decision. Those five states experienced similar crime reductions three years earlier than the rest of the nation.
  • After Roe, states that made abortion more readily accessible experienced greater crime reduction than those that didn’t.
  • This effect was concentrated among people under the age of 25 (those who would have been alive when abortion was legal). No similar crime reduction was detected in people older than the Roe decision.

Although the conclusion has been challenged over the years, the results have held up.

So, if you believe the Freakonomics abortion premise, one of the unintended consequences of yesterday’s Supreme Court ruling overturning Roe v. Wade will be the opposite of the happy result we experienced in the mid-90s - we should expect to see a substantial rise in the US crime rate roughly 20 years from now.