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Why do some street corners attract criminals and others don’t? Criminologist George Tita and colleagues use math models to explain urban crime patterns and predict the efficacy of police interventions. “Crime is a function of a motivated offender, a suitable victim, and the absence of governance,” says Tita. “Criminals follow patterns just like everyone else in their daily lives.” (Credit: Steve Zylius/UC Irvine)

UC IRVINE (US)—A new mathematical model reveals how urban crime hot spots form and spread, and suggests that two distinct types of high-crime areas respond differently to suppression tactics.

Study findings, published recently in Proceedings of the National Academy of Sciences, could help law enforcement agencies adopt more effective crime prevention strategies and tailor their approach to concentrated criminal activity.

Illegal activity follows a discernible pattern, says UC Irvine criminologist George Tita. “Criminals forage for opportunities to commit crimes, much like bees search for pollen or butterflies for nectar. Foraging patterns are predictable, whether you look at human or insect behavior.”

Among other variables, the mathematical model factors in the location of crime target—such as homes, cars, and people—and the chance of getting caught, based on police presence, environmental cues and information offenders may have gleaned from previous crimes.

Using a decade of data from the Los Angeles Police Department, researchers identified two main kinds of hot spots: supercritical and subcritical.

The first are formed when small spikes in such crimes as residential burglary and auto theft build up, creating a local crime wave. In the second, a large spike in crime—often drug-related—draws offenders to a central site.

Law enforcement efforts in the two types of hot spots have very different outcomes, the study found. “Stepped-up policing will stop crime in a subcritical area, but police involvement in a supercritical area will simply shift crime to surrounding neighborhoods,” says Tita, associate professor of criminology, law and society.

He worked with UCLA associate professor of anthropology Jeffrey Brantingham along with Andrea Bertozzi and Martin Short of UCLA’s mathematics department on the study, which was supported by the National Science Foundation.

The team, now investigating whether the model can be applied to crime worldwide, has received funding from the Office of Naval Research to see if it can shed light on insurgent groups in Iraq and Afghanistan.

Such collaboration among criminologists, anthropologists, and mathematicians may be key to preventing illegal behavior, Tita says.

“Crime is a function of a motivated offender, a suitable victim, and the absence of governance,” he says. “Criminals follow patterns just like everyone else in their daily lives.”

UC Irvine news: www.uci.edu