# Mapping Gang Turf

A new paper from P. Jeffrey Brantingham, an anthropologist at UCLA, uses a mathematical model for hunting to map street gang territory. From the UCLA Pressroom:

“The way gangs break up their neighborhoods into unique territories is a lot like the way lions or honey bees break up space,” said lead author P. Jeffrey Brantingham, a professor of anthropology at UCLA.

Using police records, the researchers mapped the activities of 13 gangs in Boyle Heights, a neighborhood just east of Los Angeles. They found the most dangerous place to be wasn’t the heart of a gang’s territory, but near the borders:

To their surprise, most of the crimes fell on the borders that the model laid between gang territories. When crime locations did deviate from the borders, they did so in a configuration that was consistent with the model. For instance, the theory predicted that 58.8 percent of the crimes would occur within one-fifth of a mile of the border between two gangs — or just under two blocks — and 87.5 percent within two-fifths of a mile of the border — or just over three blocks. Overall, 99.8 percent of crimes could be expected to occur within one mile of the border, according to the theory.In fact, the team found that 58.2 percent occurred within two blocks of the border and 83.1 percent within just over three blocks of the border; in total, 97.7 percent of the crimes took place within one mile of the border between gangs.”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 co-author Martin B. Short, an assistant adjunct professor of mathematics at UCLA.

Apparently Chicago could use this model, and fast: gang homicides are way up.

#### Jason

I'm a little confused by the geography on this. They looked at a 6.5 square mile area, divided into 13 gang territories. They established that 97.7% of crimes took place within a mile of one of the boundaries between gangs? Isn't almost every square inch of territory in the region within a mile of a boundary? Not questioning the research - just looking for more detail about how this is helpful?

#### Uthor

"They found the most dangerous place to be wasn’t the heart of a gang’s territory, but near the borders"

Isn't that kind of obvious? You'd think the place where gangs interact wtih each other would be more dangerous than the center of their home turf. What we be the point of creating a gang if you can't keep the danger away from your home?

#### JorgXMcKie

Why was anyone surprised? In the entire history of human war, *most* of the violence occurred near the borders, not in the capitals. Sheesh.

#### AJ

" They found the most dangerous place to be wasn’t the heart of a gang’s territory, but near the borders"

Who edits these no-name posts? Can you please tell them that Correlation does not imply causation?

Saying the borders are the most dangerous place to be is like saying hospitals are the most dangerous place to be because of all the deaths that occur there.

#### frankenduf

actually, hospitals are dangerous due to the concentration of infectious vectors there

#### Ruteger

Researchers also found that most of the deaths in WWI and WWII happened on the front lines.

#### AJC

Interesting. It makes sense. Borders are to be guarded, while the internal areas are presumed safe.

#### Shane L

What if a city was dominated by a single criminal gang? I've heard that Japanese police tended to tolerate the yakuza gangsters there to some extent, and it has a very low crime rate. I don't know for sure, but might it be that yakuza gangs create monopolies of crime in cities, so that there are few borders between rival gangs?

If criminal gangs are going to exist, maybe it's better to have a small number of gangs with local monopolies on organised criminal enterprise, rather than lots of violently competing gangs?

#### howcheng

Japanese cities are generally safe because Japanese culture is generally honest. Yakuza have little or nothing to do with it.

#### Voice of Reason

Yes, we are more complicated than other animals. You only see that kind of crime and violence in industry that lack any kind of regulation or government oversight. With legimate businesses, you don't see fighting and murders. Civiality and government intervention is what has seperated us from animals.