EYE ON THE SPARROWS:

Do cameras stop crime?: What has been learned in Chicago (Steve Chapman, February 20, 2011, Chicago Tribune)

This is one of Mayor Richard M. Daley's proudest achievements, but the estimated 10,000 devices now in operation are not enough for him. He once expressed his intention to keep adding cameras until there is one "on every street corner in Chicago." [...]

Nancy La Vigne, director of the Justice Policy Center at the Urban Institute in Washington, has directed a study of the impact of cameras in Chicago, Baltimore and Washington, D.C. Her preliminary findings, due to be finalized and published this year, are that they can indeed curb crime — and at a bargain price.

Her team of researchers looked at two high-crime neighborhoods on Chicago's West Side, Humboldt Park and West Garfield Park. In Humboldt Park, she told me, they found "a significant decrease in total monthly crime numbers," including property crime and violent crime. They found no evidence that the cameras merely pushed crime into other areas. In West Garfield Park, on the other hand, they saw "no impact," possibly because there were fewer cameras.

On the cost-effectiveness test, though, La Vigne says the cameras were a solid success. For every $1 of costs, they yielded $4 of societal benefits (reduced crime, savings in courts and corrections, less suffering for victims), despite their failure in West Garfield Park.

In Baltimore, where cameras are concentrated in downtown and monitored actively 24 hours a day (as distinct from the more passive approach in Chicago), La Vigne found the impact on violent crime was even greater — and the benefits exceeded the costs by 50 percent. (In Washington, which deployed only a small number of cameras, they found no effect.)