News Release

Adding windows to vacant houses and clearing vacant lots reduces gun violence, saves money

Every dollar spent remediating abandoned buildings and vacant lots could return hundreds of dollars and avert gun violence 39 percent

Peer-Reviewed Publication

University of Pennsylvania School of Medicine

PHILADELPHIA -- Each dollar spent repairing abandoned buildings and vacant lots reduces neighborhood gun violence and yields, respectively, a $5 and $26 return on investment (ROI) to taxpayers, and a $79 and $333 ROI to society at large through steps like installing working windows and doors in abandoned buildings, as well as removing trash and debris, and planting grass and trees.

Numerous Penn studies have associated blight remediation with a reduction in violent crime, but this study, published today in the American Journal of Public Health from researchers at the Perelman School of Medicine and the Wharton School at the University of Pennsylvania, is the first to report the cost-benefit and percentage reduction estimates for urban blight and firearm violence.

Gun violence in the United States is higher than in any other developed nation, and the majority of fatal violence committed in the United States involves firearms. Every year about 100,000 people are shot in the United States, according to the Centers for Disease Control.

"The immeasurable pain and void left when lives are lost to firearm violence sends a ripple effect through families and neighborhoods," said the study's lead author Charles C. Branas, PhD, a professor of Epidemiology and director of the Penn Urban Health Lab. "This study demonstrates sustainable, replicable strategies that successfully reduce firearm violence. They can transform communities across the country, save lives, and provide well more than a full return on investment to tax payers and their communities."

Studying over 5,000 abandoned buildings and vacant lots, and their impact on firearm and nonfirearm violence in Philadelphia, the team found that firearm violence decreased 39 percent in and around areas where windows and doors were restored on abandoned buildings, and decreased 5 percent in and around vacant lots that had been well maintained - decreases sustained up to nearly four years after the intervention. Neither revitalization method significantly affected nonfirearm violence rates, however, pointing to the distinct impact that blight remediation efforts can have on the misuse of illegal firearms in challenged urban communities.

Comparing rehabbed, previously abandoned buildings, to a randomly selected, matched group of abandoned buildings that had not been treated, as well as remediated vacant lots with blighted lots, the team recorded Philadelphia Police Department firearm violence statistics monthly for both groups.

Previous Penn studies have shown that remediating blighted urban spaces can reduce crime and yield numerous health benefits including helping residents feel safer, and have significantly lower heart rates than those near blighted lots. Remediating blighted urban spaces is also now being shown to have crime and violence-reducing effects in multiple other cities. Additional Penn research recently mapped paths of urban males to assess how to minimize their violence risk and another study published earlier this year associated street lights, parks, and public transportation with lower youth homicide rates.

The authors note that future trials and studies in other cities would be valuable in further demonstrating replicability and reveal insights into the types of neighborhoods and implementation methods that can yield the best reductions in firearm violence.


Co-authors, all from Penn, include Charles C. Branas, PhD, Michelle C. Kondo, PhD, Sean M. Murphy, PhD, Eugenia C. South, MD, Daniel Polsky, PhD, and John M. MacDonald, PhD.

This study was funded in part by the National Institutes of Health (R01AA020331), the Centers for Disease Control and Prevention (R49CE002474 and U01CE002698), and the Robert Wood Johnson Foundation.

Penn Medicine is one of the world's leading academic medical centers, dedicated to the related missions of medical education, biomedical research, and excellence in patient care. Penn Medicine consists of the Raymond and Ruth Perelman School of Medicine at the University of Pennsylvania (founded in 1765 as the nation's first medical school) and the University of Pennsylvania Health System, which together form a $5.3 billion enterprise.

The Perelman School of Medicine has been ranked among the top five medical schools in the United States for the past 18 years, according to U.S. News & World Report's survey of research-oriented medical schools. The School is consistently among the nation's top recipients of funding from the National Institutes of Health, with $373 million awarded in the 2015 fiscal year.

The University of Pennsylvania Health System's patient care facilities include: The Hospital of the University of Pennsylvania and Penn Presbyterian Medical Center -- which are recognized as one of the nation's top "Honor Roll" hospitals by U.S. News & World Report -- Chester County Hospital; Lancaster General Health; Penn Wissahickon Hospice; and Pennsylvania Hospital -- the nation's first hospital, founded in 1751. Additional affiliated inpatient care facilities and services throughout the Philadelphia region include Chestnut Hill Hospital and Good Shepherd Penn Partners, a partnership between Good Shepherd Rehabilitation Network and Penn Medicine.

Penn Medicine is committed to improving lives and health through a variety of community-based programs and activities. In fiscal year 2015, Penn Medicine provided $253.3 million to benefit our community.

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