Tag Archives: Andrew Papachristos

Analysis of the non-fatal gunshot social network in Chicago

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Sociologist Andrew Papachristos has a recent paper looking at the social networks involved in non-fatal gunshots in Chicago:

Papachristos constructs a social network—not a virtual one in the Facebook sense, but a real one of social connections between people—by looking at arrestees who have been arrested together. That turns out to be a lot of people in raw numbers, almost 170,000 people with a “co-offending tie” to one another, with an average age of 25.7 years, 78.6 percent male and 69.5 percent black. It’s also a large percentage of all the individuals arrested: 40 percent of all the individuals arrested during that period.Within the entire group, the largest component of that whole co-offender group has 107,740 people.

Within the timeframe—from 2006 to 2010—70 percent of all shootings in Chicago, or about 7,500 out of over 10,000, are contained within all the co-offending networks. And 89 percent of those shootings are within the largest component.

Or, to put another way: the rate of gunshot victimization (nonfatal + fatal) in Chicago is 62.1 per 100k. Within a co-offending network, it’s 740.5—more than 10 times higher.

This sounds very similar to his research on murders: being part of a particular social network dramatically increases the risk of being part of a shooting. One implication is gun crime in Chicago isn’t simply about being in a disadvantaged neighborhood or in the wrong place at the wrong time; it is about how you are tied to other people.

The article goes on to an interesting interview where Papachristos talks about data issues (collecting the right data, being able to put it into network form) and translating findings such as these into policy choices.

Social network analysis of Chicago violence show differences in risk, differences compared to Boston

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Read a summary of recent research by sociologist Andrew Papachristos about social networks and violence in Chicago:

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.