Study finds "greening" can help Philadelphia fight crime
Clean and cared-for vacant lots were found to deter criminals, improve safety
October 2, 2012, 11:26 pm·
Preliminary research at Penn shows that one way of deterring criminal activity in Philadelphia is as easy as cleaning up vacant lots. And it’s cheap.
Eugenia Garvin, a first-year resident in Penn’s Department of Emergency Medicine, conducted research indicating that cleaning and caring for vacant lots makes residents feel safer and may also reduce crime. The study was published in the journal “Injury Prevention” in August 2012.
The clean-up process, called “greening,” includes clearing trash and planting grass and trees in the lots, as well as installing a simple fence around the perimeter with openings so that people can enter.
The study took two clusters in Philadelphia, each consisting of two vacant lots adding up to between 3,000 and 5,500 square feet per cluster. One cluster was greened, and the other was left as a control. The researchers then analyzed the results with respect to crime numbers and the overall feeling of safety by the community.
Garvin’s research was a follow up to a retrospective quasi-experiment led by Penn professor of epidemiology Charlie Branas that looked at greened vacant lots over the last 10 years and showed a corresponding drop in gun crimes.
Garvin’s experiment took it a step further by conducting a randomized, controlled study.
“A randomized, controlled study is the gold standard in research to really give you the best evidence to say that the greening is directly linked to the evidence,” Garvin said. The study “prospectively randomized vacant lots either greening or not greening to see what happens to crime, and to see what happens to how safe people feel.”
“We demonstrated that people do feel safer with the greening,” she added.
As for crime, “we weren’t able to make any strong conclusions based on crime because our numbers were so small,” she said. “There were definitely trends that showed crime decreased, but we really cannot make any conclusions based on that.”
Garvin is currently planning a larger study that she hopes will be more conclusive regarding crime.
Branas lauded Garvin’s efforts and said it was an important step in the process of studying the relationship between greening and crime.
“It’s the first time a researcher has gone out and made the connections to do this,” he said. “So her study is a very big deal in that regard.”
While Garvin’s study was relatively small, Branas said the potential to expand the project is large and could have exciting implications.
The greening process was overseen by the Pennsylvania Horticultural Society, which managed all operational aspects of the project and employed landscaping contractors to do the greening.
Bob Grossman, the director of PHS, said greening vacant lots is inexpensive.
“To do the installation, which is initial cleaning, bringing in top soil, planting grass, trees and putting up the fence, it’s about a dollar per square foot,” including all material, labor and management costs, Grossman said.
He added that the annual cost for maintenance for vacant lots is about 12 to 14 cents per square foot.
“It’s a relatively simple and inexpensive intervention which can have a broad impact,” Garvin said.
There are over 40,000 vacant lots in Philadelphia, according to PHS. “I would say at least three quarters of the 40,000 have not had any kind of maintenance, probably higher than that,” Grossman said.
The real impact of greening vacant lots was driven home by Vice President for Public Safety Maureen Rush, who said greening “creates a feeling of ownership and a sense that someone cares. Criminals … have a tendency to not want to go places that look cared for.”