"They say they believe in freedom and share our values. They say a few bad apples shouldn’t bring down judgment on their entire kind. Don’t be fooled. Though they walk among us with impunity, they are, in the words of Henry Farrell, a political scientist at George Washington University, “a group that is notoriously associated with terrorist violence and fundamentalist political beliefs.” They are engineers. Farrell, of course, was kidding. He posted that comment on a blog shortly after Umar Farouk Abdulmutallab (confessed Al Qaeda operative and engineering student) tried to blow up an airliner over Detroit last winter. But the satire was rooted in a statistical fact: in the ranks of captured and confessed terrorists, engineers and engineering students are significantly overrepresented. Maybe that’s a numerological accident. The sociologist Diego Gambetta and the political scientist Steffen Hertog don’t think so."