PHILADELPHIA – Fixing up abandoned buildings in the inner city doesn’t just eliminate eyesores, it can also significantly reduce crime and violence, including gun assaults, researchers from the University of Pennsylvania and Penn’s Perelman School of Medicine report in the first study to demonstrate the direct impact of building remediation efforts on crime. The findings were published this week in the journal PLOS ONE.

The research team, which included Michelle Kondo, PhD, a former research fellow at the Perelman School of Medicine now a scientist with the USDA Northern Research Station, John MacDonald, PhD, a professor of criminology at Penn, and Charles Branas, PhD, a professor of epidemiology at the Perelman School of Medicine, found a significant decrease in serious and nuisance crimes in areas around remediated buildings after Philadelphia began enforcing an ordinance requiring owners of abandoned buildings to improve their facades and install working doors and windows in 2011. The most significant reduction (down by 39 percent) occurred for gun assaults around remediated buildings in the year following improvements.

“Replacing broken windows and doors is an effective deterrent of crime—and a low-cost alternative to demolishing abandoned buildings,” MacDonald said. “During a time when big cities like Philadelphia are looking to tackle issues of crime and violence, this study points to a potentially effective tactic for municipalities to continue or implement in helping make their neighborhoods safer and ultimately improving health outcomes.”

Prior research suggests that vacant and abandoned places have a significant and negative impact on community health and safety. The “broken windows” theory proposes that abandonment sends a signal to would-be offenders that committing crimes is acceptable and will likely go unchallenged or unseen. A sister study of abandoned land, not buildings, conducted by Branas, MacDonald and others in 2011 found an association between greening remediation of vacant lots and reduced risks of neighborhood violence, stress, and sedentary behavior. Other studies have found associations between boarded-up buildings and drug-related deaths and sexually transmitted diseases.

“City-wide, we found significant reductions in total crimes, assaults, gun assaults, robberies and nuisance crimes associated with ordinance compliance,” said Kondo, lead author of the study. “This could be the ‘broken windows theory’ in action, with new doors and windows and a newly cleaned building facade signaling to potential offenders that a property is occupied and crime is not tolerated.”

To address the 40,000 or so vacant properties tallied up in Philadelphia in 2010 and the issues that came with them, the city started enforcing a “Doors and Windows Ordinance” in 2011.

Researchers found that of the 2,356 buildings cited by the Philadelphia Department of Licenses and Inspections, 29 percent complied with the ordinance between January 2011 and April 2013. The team then compared the number of reported crimes and acts of violence at these “treatment” sites, where abandoned building owners had complied with the ordinance, to sites that had not complied, within one-half of a mile.

The crime and violence classifications included: all crimes, assaults, gun assaults, robberies, property crimes (burglaries and thefts), narcotics sales and possession, and nuisance crimes (vandalism, illegal dumping, public drunkenness, and disorderly conduct).

Compliance with the ordinance was associated with significant decreases in many of the crime and violence categories. City-wide, in areas around abandoned buildings that were remediated, over the 12 month average follow-up period in the study, there was an estimated 19 percent reduction in assaults, 39 percent reduction in gun assaults, and a 16 percent reduction in nuisance crimes. The size and significance of some of these effects, however, varied by section of the city.

Control sites were not statistically different from treatment sites in terms of the median age of the surrounding residents, their household income, education level, or poverty level.

“This study provides useful evidence that cities can directly impact some of their most pressing public health challenges, like violence, by changing the places within which their residents live, work, and play, as opposed to relocating residents as has been done in the past,” Branas said. “These sorts of place-based programs are gaining credibility as practical and low cost, yet potentially high-return, health and safety solutions when compared to other options.”

Co-authors include Danya Keene, PhD of the Yale University School of Public Health and Bernadette Hohl, PhD of the Rutgers University School of Public Health and School of Criminal Justice.

The study was supported in part with funding from the Robert Wood Johnson Health & Societies Program at Penn and a U.S. Centers for Disease Control grant to the Penn Injury Science Center.