Wednesday, September 30, 2015

Uncovering the Great Murder Mystery



In 2010 Vanessa Barker published an intriguing study just released on the internet: Explaining the Great American Crime Decline.

I love this study.

Barker reviews three studies on the crime decline: Frank Zimring’s The Great American Crime Decline, a report by Goldberger and Rosenfield and a book by Wallman and Blumstein, The Crime Drop in America.

You might think the crime decline topic is old turf with explanatory paths we’ve walked many times: less street cocaine, bigger and fuller prisons, tougher policing, smarter policing, legal abortions.

Alas, says Barker, none of those standard stories emerge from the research intact.

INSIGHTS FROM URBAN ECOLOGY

Barker moves away from standard stories onto Insights from Urban Sociology. Crime theorists will recognize references to collective efficacy and neighborhood structure. For those unfamiliar with crime theory, SafeGrowth is a megamenu of these same insights. Probably why I love the study...duh!

The changing structure of downtowns and changing youth culture falls squarely into these insights. Such changes help build more cohesive neighborhoods, not in places like Ferguson but in enough places to make a difference.

These insights include social and environmental factors this blog has held front and center, like business associations, non-profits, schools, social services, cultural activities, transport systems, and housing. They include examples of collaborative commons and social cohesion.

THE IMMIGRATION BOMB

That’s when Barker drops the bomb! When she re-examined urban ecology studies on immigration she discovered how increasing immigration has helped reduce crime, not increase it!

“Sampson…suggests that increased immigration in the 1990s sparked urban renewal and economic growth in immigrant-dense neighborhoods like Queens and Bushwick in New York, the West Side in Chicago, South Central Los Angeles, and cities like Miami. The influx of immigrants corresponded with increases in income and decreases in poverty.”

THE NATTERING NUMPTIES

I’d love to see that debate in elections now underway in Canada, and next year in the U.S. Sadly what we get instead is hollow sound-bite nuggets from a bunch of nattering numpties.

Case in point: Last week the NDP party in Canada proposed to hire 2,500 more cops. They want to cut crime on Canadian streets…streets where most crime is still declining!

Pockets of Crime expands urban ecology theory -
collective action by residents can turn the tide,
but only when physical conditions are right

INFINITE MONKEY THEOREM

Sadly the standard stories persist, lately in the theory that crime declines resulted from increased security worldwide (in technical terms, guardianship). And we are served up a buffet of advanced statistical techniques that hit and peck at data in shiny, new datasets.

It’s a kind of infinite monkey theorem for big crime data. Remember the theory that predicted the monkey who hits and pecks keyboard keys for infinity will almost surely end up creating Hamlet.

I say leave the monkey alone! Barker and colleagues are onto something, something we’ve known for a long time.