Crime--It's Largely A Question Of Where You Are

I've read over the years that lifestyle choices, such as visiting bars and nightclubs, using drugs or abusing alcohol, and so on, are major factors in determining your risk of being a victim of a violent crime. The reason these are factors are because they put you into situations or places where crimes are likely to happen. To emphasize the latter point, I came across the following in an article on "predictive policing":

. . . Crime does not randomly disperse through cities. For example, research has shown that half the crime in Seattle occurs on 4.5 percent of that city’s streets; just over 3 percent of street addresses and intersections generated half the crimes in Minneapolis; and 8 percent of street blocks accounted for 66 percent of robberies in Boston.

Researchers have developed two theories for why some areas are subject to higher rates of crime; near repeat theory and risk terrain modeling. Near repeat theory hypothesizes that once a particular location has been hit by a crime it is more likely nearby locations will be hit too. For example, studies have shown that burglaries are “contagious.” One study found that “houses within 200 meters of a burgled home were at an elevated risk of burglary for a period of at least two weeks.” Why? Possibly because a successful burglary advertises similar vulnerabilities in other properties in a neighborhood.

Risk terrain modeling maps various risk factors to identify areas where crimes are more likely to occur. For example, Rutgers University computational criminologist Joel Caplan mapped for Irvington, New Jersey four crime risk factors correlated with shooting incidents. The risk factors were the locations of gang member residences, public bus stops, schools, and facilities like bars, clubs, fast food restaurants, and liquor stores. He found that “the likelihood of a shooting happening at particular 100-foot-by-100-foot places in Irvington during 2007 increases by 143 percent as each additional risk factor affects that place.”

In June, Brantingham and his colleagues published a study that applied Lotka-Volterra equations used by biologists for decades to determine the hunting ranges of animals in the wild to map the territories of street gangs [PDF]. Their model predicted that 59 percent of gang crimes would occur within two blocks of a border between two gangs and 87.5 percent would occur within about three blocks. When the researchers mapped more than 500 crimes attributed to 13 gangs in a specific area of Los Angeles, they found in fact that 58 percent and 83 percent occurred within two blocks and three blocks of a border respectively.

"You would think that we're more complicated than other animals, so a model this simplistic shouldn't work, but I was surprised that it fit as well as it did," said study co-author Martin Short, an assistant adjunct professor of mathematics at UCLA in Wired UK. This research may eventually be used to identify zones to be more intensively patrolled by police with the goal of disrupting assaults and murders perpetrated by gangs.