A plunge in US violent crime over the last two years despite the economic downturn appears to confirm what experts have long known -- that poverty alone does not drive delinquency.
The latest figures released by the Federal Bureau of Investigation (FBI) show the lowest level of violent crime since the 1960s and a 5.5 percent decline in 2010 alone, following a 5.3 percent drop the previous year.
Robbery is also down nationwide -- by 9.5 percent in 2010 and 8.0 percent in 2009 -- despite soaring unemployment and a grim economic outlook.
Experts differ on what could explain the decline and insist more research is necessary, but say they have long viewed poverty as a poor indicator for violent crime and a weak one at best for property crime.
"There is no single satisfying answer to what causes changes in our crime rate, just like there is no single cause of weather," said Catherine Gallagher, a criminologist at Virginia's George Mason University.
"This is terribly unfulfilling for academic and armchair criminologists, and makes for a terrible soundbite."
Losing a job can lead to anger and desperation, but it can also mean spending more time with family and being at home during the day, cutting down on burglaries, she said.
And for law enforcement agencies, shrinking budgets can translate to less police, but can also motivate chiefs to deploy limited resources more effectively.
Experts point to myriad factors that have steadily reduced crime since the 1980s and early 1990s, when the crack cocaine epidemic devastated US cities.
Better policing, record incarcerations and the proliferation of cell phones have all likely contributed to the general decline over the last two decades, including a 40 percent drop in crime from 1993 to 2000.
But Alfred Blumstein, a criminology professor at Heinz College of Carnegie Mellon University, said none would explain the dramatic shift in 2009 alone.
"There were two things that happened in 2009. One was a recession, and that should have made things worse, and the other was the election of an African-American president," Blumstein said.
He pointed to an "Obama effect" that may have mitigated feelings of social inequality and discrimination, seen as factors in previous crime waves.
Blumstein acknowledged the theory remains "speculation" for now, but said it was consistent with statistics that show a decline in the arrest of African-Americans and a rise in arrests of Caucasians in 2009.
Such findings have added significance because the arrest rate of blacks versus whites is 8-1 for robbery and 6-1 for murder, according to Blumstein.
Gary LaFree, a criminologist at the University of Maryland, takes a similar approach, insisting that crime is motivated less by poverty than by history, and the perceived "legitimacy" of social and political institutions.
"In the 1960s (when crime rates steadily rose), we were questioning every single institution in American society, huge questioning of the political system, the economic system, the family system," he said.
The spike in crime during the 1980s, on the other hand, was the "bad accidental luck" of the discovery of crack cocaine, which created "an incredibly addictive and lucrative market that was totally unregulated."
The more recent decline might therefore be related to the increased respect for institutions in the wake of the September 11 attacks and the natural decline after the explosive introduction of crack, according to LaFree.
William Bratton, who served as police chief in both New York and Los Angeles, agreed that poverty in and of itself does not cause crime, but noted that prolonged and severe economic downturns can be dangerous.
In addition to foreclosing economic opportunities, "they perpetuate an underclass culture that fails to educate and socialize young men," he wrote last week in a guest posting on the Freakonomics blog.
"As these young men grow, they become the foot soldiers for crime."
Bratton also warned that long-term cuts in police budgets could leave departments ill-prepared for future crime waves, as when a fiscal crisis in New York City weakened the police ahead of the emergence of crack in the 1980s.
"With these dual factors -- poorly socialized youth and weakened police departments... the long-term outlook for crime could worsen significantly, and the positive crime trends of the past 20 years could be reversed."
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