Wednesday, November 7, 2007

Malcolm Gladwell has a new, less than flattering, article about criminal profiling

A profile isn't a test, where you pass if you get most of the answers right. It's a portrait, and all the details have to cohere in some way if the image is to be helpful. In the mid-nineties, the British Home Office analyzed a hundred and eighty-four crimes, to see how many times profiles led to the arrest of a criminal. The profile worked in five of those cases. That's just 2.7 per cent, which makes sense if you consider the position of the detective on the receiving end of a profiler's list of conjectures. Do you believe the stuttering part? Or do you believe the thirty-year-old part? Or do you throw up your hands in frustration?


Brussel did not really understand the mind of the Mad Bomber. He seems to have understood only that, if you make a great number of predictions, the ones that were wrong will soon be forgotten, and the ones that turn out to be true will make you famous. The Hedunit is not a triumph of forensic analysis. It's a party trick.