Take, for instance, a 2013 paper, published with Yale colleague Christopher Wilderman in the American Journal of Public Health. It’s set in a community in Chicago with a litany of familar risk factors: half of all households were led by a single female; 43 percent of the 82,000 residents had less than a high-school education; a third of households were below the poverty line. And the homicide rate, over the five years of the study, was 55.2 per 100,000, about four times the citywide rate (Daniel Hertz’s maps of homicide rates by police district are a good way of putting that in context; it’s high.)…
Simply being arrested during this period increases the aggregate homicide rate by nearly 50%, but being in a network component with a homicide victim increases the homicide rate by a staggering 900% (from 55.2 to 554.1)…
Even in this extremely abstracted form, from a third paper by Papachristos you can see a remarkable contrast between gang violence in Chicago and Boston. Each node is a gang; each line is a homicide or shooting; each bidirectional line is a reciprocal homicide…
Chicago’s social network of homicide is a knotty mess: 98 percent of all Chicago gangs were connected within the city’s homicide network during that timeframe, 32 percent higher than Boston’s shooting network. The network density of black gangs in Chicago is particularly intense, 30 percent compared to 4.5 percent for Latino gangs…
And a place to start for gathering more data—as Papachristos points out, his analysis is limited to people doing bad things. Robert Sampson, the Harvard (by way of Chicago) sociologist, has done pioneering work, most recently in his book Great American City, showing how positive social networks reduce crime and improve public-health outcomes in socially-organized neighborhoods like Chatham. Another possible implication is figuring out what kinds of networks “inoculate” people from violence.
Looks like a good summary of some interesting research. On one hand, this should be reassuring to the public: the perception is that crime rates in Chicago are out of control (even as they have declined in Chicago over the years and in many American cities) yet much of the violent crime is in the hands of a relatively small group of people. On the other hand, the density of violence in Chicago suggests there are some serious issues in particular social interactions and locations that are not easy to solve.
I’m also reminded of the work of sociologist Sudhir Venkatesh who has argued in several books that gangs in Chicago as well as more informal black market networks might be considered “efficient” or “rational” in what they do because of a lack of legitimate opportunities in poor neighborhoods. Whereas legal businesses might seek the best way to make profits, social networks in disadvantaged neighborhoods make do with what they have, even if the means are not legitimate. This doesn’t condone violence or other illegal behavior but Venkatesh’s work shows these aren’t haphazard or chaotic social networks and interactions.
Legally Sociable 