Abandoned properties in Baltimore, MD. (AP Photo)

Abandoned buildings in Philadelphia. (Photo by Jukie Bot. Flickr Creative Commons license.)

The loss of manufacturing jobs, urban disinvestment, foreclosures, and urban flight in cities like Baltimore and Philadelphia have led to a spike in the number of abandoned and vacant properties. The presence of these boarded up homes leads to poorer health and feelings of hopelessness among residents, increased mortality among drug users and the spread of sexually transmitted disease, studies have shown. And, according to the broken windows theory, abandoned buildings also lead to an increase in crime.

A recent study published by researchers from the University of Pennsylvania also supports the existing studies by finding that doing facelifts on abandoned buildings can dramatically reduce crime in those neighborhoods.

Before and After Photos of Renovated Vacant Properties. This figure shows four properties that received doors-and-windows remediation. Pink posters on doors of properties shown in the upper left- and lower right-hand quadrants notify the owner of a date by which the structure must be in compliance or face penalty. (The work is made available under the Creative Commons CC0 public domain dedication)

In 2010, Philadelphia counted about 40,000 abandoned properties throughout the city. And, in 2011, they implemented one solution—an ordinance requiring property owners of vacant buildings on blocks that are more than 80 percent occupied to improve the building’s façades and install functional windows and doors or face a fine.

Of the 2,356 buildings cited by the Licensing and Inspection Department, researchers found 29 percent complied with the ordinance between January 2011 and April 2013, The team then compared crimes at the sites where remediation had taken place to the sites where buildings remained in non-compliance, within one half-mile.

Over the average 12-month follow-up period, the researchers found that around the updated buildings, crime declined, including a 19 percent reduction in assaults, 39 percent reduction in gun assaults, and a 16 percent reduction in nuisance crimes.

“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,” said lead author Michelle Kondo, a former research fellow at the Perelman School of Medicine now a scientist with the USDA Northern Research Station.

Researchers said the study presents a viable solution to cities facing similar challenges.

“Replacing broken windows and doors is an effective deterrent of crime—and a low-cost alternative to demolishing abandoned buildings,” said John MacDonald, a professor of criminology at Penn and co-author of the study, in a statement. “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.”