But first, the efficacy of profiling when you're just using plausible guesses:
The extraordinary lengths the German authorities went to after 9/11 to track down potential terrorists are a stark example of how useless profiling can be. They collected and analysed data on over 8 million individuals living in Germany. These people were categorised by demographic characteristics: male, aged 18 to 40; current or former student; Muslim; legally resident in Germany; and originating from one of 26 Islamic countries. Then they were sorted into three further categories: potential to carry out a terrorist attack (such as a pilot's licence); familiarity with locations that could be targets (such as working in airports, nuclear power plants, chemical plants, the rail service, labs and other research institutes); and studying the German language at the Goethe Institute.
With the help of these categories authorities whittled the 8 million down to just 1689 individuals, who were then investigated, one by one. Giovanni Capoccia, an Oxford-based political scientist who analysed this case, reported that not one of them turned out to be a threat. All the real Islamic terrorists arrested in Germany through other investigations were not on the official "shortlist" and did not fit the profile.
However, after partial clue acquisition, we discover....
The next move was to find out what they had studied - and we tracked down 178 of our 196 cases. The largest single group were engineers, with 78 out of 178, followed by 34 taking Islamic studies, 14 studying medicine, 12 economics and business studies, and 7 natural sciences. The over-representation of engineers applies to all 13 militant groups in the sample and to all 17 nationalities, with the exception of Saudi Arabia.
I'm tired of typing "blockquote", so I'll just tell you it's possible that Saudi Arabia is an exception because it's easy for engineers to find jobs there.
We also collected data on non-Muslim extremists. We found that engineers are almost completely absent from violent left-wing groups, while they are present among violent right-wing groups in different countries. Out of seven right-wing leaders in the US whose degrees we were able to establish, four were engineers: for example, Richard Butler, the founder of the neo-Nazi group Aryan Nations, was an aeronautical engineer, and Wilhelm Schmitt, leader of the right-wing, extreme anti-government, pro-localism group known as the Sheriff's Posse Comitatus, was an engineer with Lockheed Martin. Among the total membership of the Islamic groups, however, the over-representation is still much higher.
This may explain why right-wing terrorists are better at killing people than left-wing terrorists, but it doesn't explain the political divide.
According to polling data, engineering professors in the US are seven times as likely to be right-wing and religious as other academics, and similar biases apply to students. In 16 other countries we investigated, engineers seem to be no more right-wing or religious than the rest of the population, but the number of engineers combining both traits is unusually high. A lot of piecemeal evidence suggests that characteristics such as greater intolerance of ambiguity, a belief that society can be made to work like clockwork, and dislike of democratic politics which involves compromise, are more common among engineers.