You know the old saw – “there are three kinds of lies: lies, damn lies and statistics.” The quip was brought to mind when I glanced at the year-end Department of Homeland Security fact sheet touting what it’s done to make us safer. Among the featured items was “increasing by more than 175 percent the number of personnel trained in techniques to identify high-risk passengers in airports.”

Call me cynical, but I always wonder when huge statistical increases are cited rather than the raw numbers themselves, especially when the statistics are being cited by government officials. And that goes double when the officials in question are from the Department of Homeland Security. But it’s not really the numbers that concern me here; it’s the program itself.

Since 2003, the Transportation Security Administration has operated a program called SPOT (Screening Passengers by Observation Techniques). T.S.A. workers are given four days of classroom instruction and one day of on-the-job-training in spotting suspicious behavior that might be indicative of terrorist intent. They then roam airports looking for passengers who appear unusually nervous or angry or determined, in hopes of preventing the next would-be Mohammed Atta from carrying out another attack.

I’m not opposed to behavior recognition, in theory. The Israelis have been using it for years quite successfully. And it makes sense to complement efforts to spot deadly weapons by concentrating at least some attention on spotting people with deadly intent...

But I strongly question whether five days is enough to train anybody in the intrinsically difficult art-science of behavior detection. And with all due respect to T.S.A. screeners, they are not Mossad agents.