Tuesday, September 19, 2006

The educated suicide bomber

I don't know how I missed this "Economic Scene" essay by Austan Goolsby, on selection bias and why some people, born and educated in the West, are willing to die to bring down the society they know best.. His point is that "some economists argue that we need to think about what makes a successful terrorist and they warn against extrapolating from the terrorists we catch."

In their new study, “Attack Assignments in Terror Organizations and the Productivity of Suicide Bombers,” two economists, Efraim Benmelech of Harvard University and Claude Berrebi of the RAND Corporation, set out to analyze the productivity of terrorists in the same way they might analyze the auto industry. But they defined the “success” of terrorists by their ability to kill.

They gathered data on Palestinian suicide bombers in Israel from 2000 to 2005 and found that for terrorists, just like for regular workers, experience and education improve productivity. Suicide bombers who are older — in their late 20’s and early 30’s — and better educated are less likely to be caught on their missions and are more likely to kill large numbers of people at bigger, more difficult targets than younger and more poorly educated bombers.

Professor Benmelech and Dr. Berrebi compare a Who’s Who of the biggest suicide bombers to more typical bombers. Whereas typical bombers were younger than 21 and about 18 percent of them had at least some college education, the average age of the most successful bombers was almost 26 and 60 percent of them were college educated.

Experience and education also affect the chances of being caught. Every additional year of age reduces the chance by 12 percent. Having more than a high school education cuts the chance by more than half.

Of course, at least for terrorists who have grown up in the West, the education probably acts as a signal of greater intelligence, rather than actually being the cause of that intelligence. In the cases where the terrorists are from the Middle East, however, the education may actually act by making comfortable with the culture of their intended targets.

Anyway, it appears the terrorists organizations are aware of these facts.

Among Palestinian suicide bombers, the older and better-educated bombers are assigned to targets in bigger cities where they can potentially kill greater numbers of people. That same idea means that the terrorists assigned to attack the United States are probably different from the typical terrorist. They will be drawn from people whose skills make them better at evading security

And what lesson can we draw from all this?

It’s only natural that terror groups would recruit native English speakers when people are clamoring for extra airport scrutiny of Arabs from the Middle East. It does not imply that the Muslim community is a more fertile ground for terrorists in Britain than in other countries.

Think of the extreme case. One of the people arrested in the liquid explosives plot (albeit on a minor charge) was a woman with a baby. London newspapers have speculated that she was planning to carry her baby onto a plane with liquid explosives in his bottle. Even if true, that does not mean we should all start suspecting that women with babies are closet terrorists. That would be rather egregious selection bias. Objectively, we should be much more suspicious of other people. We see only the mother because the terrorists have an overwhelming incentive to find the one unusual terrorist who will outsmart our defenses.

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