Beware of basketball

The newest video on the main page of the Freakonomics blog (They don't allow embedding, so go to the site if you want to watch the video) concerns itself with the assertion that sports may cause crime. This comes from a French political scientist who claims that:

The practice of sport never reduces the number of crimes”. On the contrary, they tend to show that such a practice “can give the opportunity to develop physical abilities useful for street crime: running, how to use impulsive behaviour, how to master the use of force.

Reading through the poorly translated interview, I'm not particularly impressed or convinced with his work. It seems like he's making the fatal mistake of confusing correlation with causation, meaning that there might be other reasons causing both the increased sport participation and the increased crime. The only way to established causation is through a controlled double-blind experiment (Hooray for AP Stat), otherwise all you get is correlation. I'm guessing that the esteemed Dr. Sébastien Roché did not take identical sportless towns, introduce sport to one of them and not the other, and then all things equal observe the differences. Not buying it.

Stephen J. Dubner, co-author of Freakonomics, offers much of the same opinion on the topic:

This strikes me as a fascinating subject, and an interesting argument, although the proof offered by Roche and his like-minded colleagues seems very thin. Their research is based on interviews with young men and shows that the more time a young man spends playing sports, the more likely he is to have committed a serious crime. But does this mean that sports are the culprit? Couldn’t it just as easily mean that the kind of young man who’s criminally inclined a) doesn’t have a job; and b) therefore has a lot of free time; which c) he spends playing sports?

So, in short, despite what a woman with an accent may tell you (you'd understand if you watched the video), send your kids to sports camp. They won't necessarily grow up to be gangsters (But I'm not making any guarantees).