July 5, 2007.

When Princeton economist Alan Krueger saw reports that seven of eight people
arrested in the unsuccessful car bombings in Britain were doctors, he wasn’t
shocked. He wasn’t even surprised.

“Each time we have one of these attacks and the backgrounds of the attackers are
revealed, this should put to rest the myth that terrorists are attacking us
because they are desperately poor,” he says. “But this misconception doesn’t
die.”

Less than a year after the Sept. 11, 2001, attacks, President Bush said, “We
fight against poverty because hope is an answer to terror.” A couple of months
later, his wife, Laura, said, “Educated children are much more likely to embrace
the values that defeat terror.” Former World Bank President James Wolfensohn has
argued, “The war on terrorism will not be won until we have come to grips with
the problem of poverty, and thus the sources of discontent.”

The analysis is plausible. It’s appealing because it bolsters the case for the
worthy goals of fighting poverty and ignorance. But systematic study — to the
extent possible — suggests it’s wrong.

“As a group, terrorists are better educated and from wealthier families than the
typical person in the same age group in the societies from which they
originate,” Mr. Krueger said at the London School of Economics last year in a
lecture soon to be published as a book, “What Makes a Terrorist?”

“There is no evidence of a general tendency for impoverished or uneducated
people to be more likely to support terrorism or join terrorist organizations
than their higher-income, better-educated countrymen,” he said. The Sept. 11
attackers were relatively well-off men from a rich country, Saudi Arabia.

Mr. Krueger, 46 years old, is one of those academics whose research extends from
the standard fare — How much more do workers with education earn? What happens
to employment when the minimum wage rises? — to, well, cool stuff. Did
Firestone factories produce shoddy tires during a period of labor unrest? (Yes)
Are rich people really enjoying life more than the rest of us? (No) Are
concert-ticket prices higher for female musicians than males? (Yes)

He began poking around this sordid subject a decade ago when he and a colleague
found little connection between economic circumstances and the incidence of
violent hate crimes in Germany. Among the statistical pieces of the puzzle a
small band of academics have assembled since are these:

• Backgrounds of 148 Palestinian suicide bombers show they were less likely to
  come from families living in poverty and were more likely to have finished high
  school than the general population. Biographies of 129 Hezbollah shahids
  (martyrs) reveal they, too, are less likely to be from poor families than the
  Lebanese population from which they come. The same goes for available data about
  an Israeli terrorist organization, Gush Emunim, active in the 1980s.
• Terrorism doesn’t increase in the Middle East when economic conditions worsen;
  indeed, there seems no link. One study finds the number of terrorist incidents
  is actually higher in countries that spend more on social-welfare programs.
  Slicing and dicing data finds no discernible pattern that countries that are
  poorer or more illiterate produce more terrorists. Examining 781 terrorist
  events classified by the U.S. State Department as “significant” reveals
  terrorists tend to come from countries distinguished by political oppression,
  not poverty or inequality.
• Public-opinion polls from Jordan, Morocco, Pakistan and Turkey find people
  with more education are more likely to say suicide attacks against Westerners in
  Iraq are justified. Polls of Palestinians find no clear difference in support
  for terrorism as a means to achieve political ends between the most and least
  educated.

Data on which all this relies are hardly perfect: Terrorists don’t fill out
elaborate questionnaires. Better-off, better-educated individuals could be
motivated if not by their own circumstances, then by the conditions of their
impoverished countrymen. Interviews of terrorists in Pakistan by Harvard
terrorism scholar Jessica Stern reveal recruiters there found the poorest
neighborhoods to be the most fertile ground, particularly among those who feel
Muslims are humiliated by the West. She says Mr. Krueger and like-minded
scholars don’t yet have enough evidence to prove anything. “We are only just
beginning to do really serious large studies in terrorism,” she says.

But the conventional wisdom that poverty breeds terrorism is backed by
surprisingly little hard evidence. “The evidence is nearly unanimous in
rejecting either material deprivation or inadequate education as an important
cause of support for terrorism or of participation in terrorist activities,” Mr.
Krueger asserts. The 9/11 Commission stated flatly: “Terrorism is not caused by poverty.”

So what is the cause? Suppression of civil liberties and political rights, Mr.
Krueger hypothesizes. “When nonviolent means of protest are curtailed,” he says,
“malcontents appear to be more likely to turn to terrorist tactics.”