The findings come from a study, published Monday in JAMA Pediatrics
, of 143 homicide cases involving adolescents ages 13 to 20 in Philadelphia between 2010 and 2012. Researchers compared the neighborhoods where the homicides took place with the neighborhoods where 155 control teenagers, who were not homicide victims, were located at about the same time as the crimes.
Using 360-degree panoramic photographs, the researchers looked at more than a dozen different features in the neighborhoods: Was there a park or empty building lot near the scene of the crime or the control scene? What kind of streets and sidewalks were at the sites?
The researchers found that the presence of streetlights, illuminated crosswalk signs and public transportation was associated with 24%, 16% and 13% lower risk of teen homicide, respectively. Parks and well-maintained vacant lots were also linked with 9% and 17% lower risk. On the other hand, sites that had stop signs and security bars on housing were at four times and nine times higher risk of having an adolescent homicide.
But it is an unanswered question whether these features had a direct role in protecting teens from violence, for instance if well-lit streets were deterring assailants. Alternatively, these features could simply be indicators of areas that tend to have high or low rates of crime in general.
"Because this study is a snapshot in time, we don't know whether these environmental elements caused homicide reductions or whether we are picking up markers of other things going on in the neighborhood," said Dr. Alison J. Culyba, advanced research fellow in the Craig Dalsimer Division of Adolescent Medicine
at The Children's Hospital of Philadelphia. In support of both possibilities, "there is a theory that busy streets (such as those with streetlights and crosswalks) encourage interactions and vibrant communities that help promote social connections and reduce crime," Culyba said. However in support of the "other things going on in the neighborhood" possibility, Culyba pointed out that areas with security bars on houses could have been high-crime areas for many years.
To get at whether environmental elements could directly reduce adolescent homicide rates, "our big next step is to utilize a lot of the features that we identified through this study and design ... interventions to really study the impact of these features," Culyba said.
Although studies have not addressed whether neighborhood improvements could bring down adolescent homicide rates, there is some research hinting that these interventions could reduce crime overall. One study in Youngstown, Ohio
, found that cleaning up vacant lots or converting them into community gardens was associated with drops in burglaries and assaults in the area. Another study
linked business improvement districts around Los Angeles with lower rates of robberies and violent crimes in those neighborhoods.
The current study focused on teen homicides that happened outdoors, which is where most of these crimes occur, Culyba said. Although the study did not define the type of homicide, the most common in Philadelphia by far is gun-related, while a minority of homicides are caused by stabbing or blunt trauma, Culyba added.
It is impossible to know how the neighborhood features in the current study might be associated with homicide rates in other urban areas, and in suburban and rural areas where the landscape is different, Culyba said.
The findings suggest that at least certain aspects of the "broken windows" police strategy could be effective, Culyba said. According to this theory, degraded public areas lead to increases in serious crime, and thus police should crack down on disorder and minor crimes to prevent more serious ones.
However the policy has been criticized in New York
and elsewhere for bringing excessive police force to low-level crimes. In a move to reduce a backlog of criminal cases, police in Manhattan will no longer arrest people who commit minor offenses
such as public urination or drinking in public. The policy shift begins this week.
"Our findings could fit into the broken windows (theory) in that helping communities to renovate or remediate areas that have the potential to be crime attractants could be a strategy that is relevant in reducing homicide rates," Culyba said. However it is important to stick to the types of interventions for which there are data supporting their effect, such as revitalizing vacant lots, repairing abandoned buildings and creating business improvement districts, she added.
There is definitely a need to do intervention studies to test whether different neighborhood features can help bring down rates of teen homicide, said Natalia E. Pane, senior vice president for research and operations at Child Trends
, a nonprofit research group and think tank.
The possibility that changing the environment might help prevent homicide is especially interesting with teens, Pane said. "With adolescents, those momentary bad decisions become (astronomical), especially when we are dealing with guns, because they are not as good at calculating risks
, and so one little tweak (in the environment) might help avoid those momentary bad decisions," she said.
However, even if these changes do lead to lower rates of adolescent homicide, the benefits could be difficult to sustain "because bigger fundamental things sweep over it, like poverty and lack of economic opportunities," Pane said.