just anecdotally, that when we green these lots, crime goes down.” Branas wanted to know more. Charles C. Branas, Ph.D., professor of epidemiology and director of the Penn Cartographic Modeling Lab, had been studying gun violence and its connection to geography and place since coming to Penn in 2000. “I had been describing various threats to health and safety for years,” he says, “and I really wanted to turn the corner and start doing something to improve health and safety.” The conversation between the two set him moving in what would be a challenging but important new direction.
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ranas’s “describing” years were powerful ones. He was principal investigator of numerous studies related to gun violence. In 2004, he and his colleagues published a nationwide study of geographic variations in firearm death that went on to be cited in landmark Supreme Court decisions on the topic. The study analyzed more than one-half million firearm deaths occurring in the 1990s for every county in the U.S. It found the risk of death by firearms equal in rural and urban areas: homicide more common in cities – not a surprise – and suicides alarmingly prevalent in the countryside, where they were largely overlooked. Branas also received one of the three major gun-violence research grants the National Institutes of Health (NIH) has awarded over the last 40 years. It funded his study on the relationship between alcohol availability and gun violence – the work he presented at the Federal Reserve Bank conference. Analyzing 677 gun assaults that occurred in Philadelphia between 2003 and 2006 (plus 684 controls randomly sampled from the city’s adult population), he showed that heavy drinking where take-out alcohol venues were plentiful significantly increased the risk of being shot. Heavy drinking in bars and taverns, even in neighborhoods rife with gun violence, turned out to be less of a risk. Published in the journal Alcoholism: Clinical and Experimental Research in 2009, the findings gave big cities a way to reduce gun violence without getting embroiled in gunrights issues. They could modify environmental factors related to alcohol: for example, limit the hours take-out
alcohol can be sold, prohibit sales to visibly intoxicated customers, crack down on public drunkenness, or selectively shut down nuisance outlets. Branas had also already hit upon the relationship between vacant properties and violence. Not long before the conference, a student of his at the time, J. Nadine Gracia, M.D., M.S.C.E. ’08 (who went on to be a White House Fellow and is now the Deputy Assistant Secretary for Minority Health), had mapped violent crime in Philadelphia, plus a host of other factors, such as vacant properties, poverty, unemployment, race, ethnicity, and education. “The map of vacant properties was almost identical to the map of violent crimes, more so than the maps we made of a dozen other well-known indicators of disadvantage,” says Branas, the senior author of the study. “The match was more than just by chance.” Gracia and Branas showed that every new vacancy in the study area corresponded to an 18.5 percent increase in violent crime and an even greater increase – 22.4 percent – in violent crimes committed with guns, but the study had limitations. The records they used had identified vacant properties overall, but didn’t differentiate between abandoned buildings and empty lots. The researchers couldn’t determine which, if either, was more responsible for gun crimes. Moreover, they couldn’t say which had come first: Had the presence of vacant properties invited crime, or had crime emptied neighborhoods, driving residents and businesses elsewhere? Grossmann’s experience resonated with their findings. He could speak to blighted lots as hot spots for crime, describe open-air drug markets – “with tables and awnings” – set up amid the weeds and debris, report on guns discovered there by his contractors and bodies found by the police. Grossmann recalled how residents had once fought the demolition of a condemned house because they feared an empty lot more. He knew that people often walked down the center of the street, giving wide berth to lots that were wildly overgrown. After the greenings, Grossman noted the disappearance of some notorious open-air markets. Residents also reported less drug activity in their neighborhoods. Neighborhood retailers corroborated these views when they com-
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