Fixing Up Places Is Easier Than Fixing People

Serious violent crime and firearm violence represent a major public health challenge in the United States. Firearm homicide is a leading cause of death in the United States, with substantial racial disparities documented over time. Serious crime and violence in the United States are also spatially concentrated in the most socially and economically disadvantaged urban neighborhoods. Hebrew University criminologist David Weisburd has referred to this empirical reality as the “law of crime concentration.”¹

Several study authors have noted that place-based approaches offer an effective means of reducing the concentration of serious crime and gun violence in the most economically disadvantaged communities.² There is a growing body of high-quality controlled and randomized trials showing that remediation of blighted vacant land and abandoned housing helps mitigate serious crime and firearm violence.^3,4

However, absent from this research has been a focus on what happens to blighted vacant land or abandoned housing once there is reinvestment with new properties. Although structural repairs to abandoned and occupied housing have been shown to help reduce serious crime and gun violence in controlled and randomized trials,^5–7 to date there are few causal studies that show whether investments in new housing and occupied structures help alleviate the concentration of serious crime and gun violence.

Asa et al. (p. 95) take up this issue in their study of the effect of the redevelopment of 254 vacant lots in Philadelphia, Pennsylvania, over a 16-year period (2007–2023) on serious violent crime and violent crimes committed with firearms. The exposure in this case was the specific repurposing of vacant lots into permanent structures, largely housing, as compared with lots that remained vacant and blighted. This study is ideal because the authors rely on a rigorous difference-in-difference design that attributes changes in violent crime and gun violence to the timing of when the vacant lot was repurposed for new housing or a building structure. Useful for public health policy, they found that among the subset of vacant lots repurposed into permanent housing or business structures, there was a statistically significant effect on aggravated assault (i.e., a reduction of 30%) and overall violence committed with firearms (a reduction of 14.7%). The gun violence reduction benefits of repurposing vacant lots, however, occurred only with permanent housing or business structures, not parking lots or fenced-off vacant lots that were maintained.

The mechanisms by which building new structures on blighted vacant lots reduces gun violence are not explained, because the study authors could not observe human activities changing around the places before and after they were repurposed. However, the study offers a view into what could be done in the future. Following the same methodology, it is possible to use cell phone data that are available to researchers to examine how, if at all, human activity around vacant lots changes after they are repurposed. Perhaps new foot traffic arrives, the level of guardianship at locations changes, or some combination of new residents and the dynamics of the places shifts after vacant lots are converted to housing and business structures.

The Asa et al. study shows no evidence that repurposed vacant lots lead to displacement of aggravated assaults and overall gun violence to nearby areas. These findings are consistent with a growing body of evidence showing minimal displacement from place-based crime prevention interventions.⁸ Places that attract gun violence may not be easily transferred elsewhere. Situational dynamics of places attracting gun violence such as open air drug markets, for example, may not easily be relocated from a vacant lot on one block to another location.

Sprucing up vacant lots to keep them in a stable and maintained condition until they can be repurposed for housing or commercial use benefits both Philadelphians and the city’s tax base. To that end, the Pennsylvania Horticultural Society’s LandCare program cleans, greens, and maintains vacant lots. New structures mean that new property taxes can be collected and neighborhoods can attract reinvestment. Although gentrification is often a concern, the more housing that is developed, the lower on average the price per unit. In short, the only way to secure more affordable housing in cities such as Philadelphia is to build more housing.

The available evidence from the Asa et al. study and others suggests, contrary to conventional wisdom in many circles, that redevelopment that spurs some degree of gentrification lowers serious crime.⁹ At the same time, it is important to recognize that gentrification can lead to displacement of existing residents if new housing and businesses lead to rising property values and higher local tax assessments. To mitigate this issue, policies such as homestead exemptions should be in place to reduce the assessed value of existing homes near new developments.

The Asa et al. study adds to the growing body of high-quality studies demonstrating that abating vacant land in an urban neighborhood can dramatically reduce serious crime and gun violence. The changes do not require large-scale structural investments from taxpayers. Rather, they require cities to provide access to vacant properties in a way that allows them to be repurposed into housing and business structures in a cost-effective way to spur redevelopment. Although this may, in some circumstances, change the social fabric of neighborhoods, it is an inevitable process of neighborhood change when new generations of residents move into a place. The alternative is stagnation and decline.

Public health policy can gain considerably from focusing on place-based changes such as those emphasized in the Asa et al. study. Redevelopment of properties may be seen as a real estate or urban planning issue; considering the degree to which gun violence and serious crime are concentrated in cities and how this issue affects population health, however, public health policies should view place-based approaches as part of the portfolio of interventions to study, test, and advocate.²

In fact, place-based public health interventions were central to the foundation of public health. Dr. John Snow shutting off the water pump at Southwark/Vauxhall after showing evidence that the cholera outbreak was worse around that location where residents obtained their water than around Lambeth is a foundational example of a place-focused public health intervention. Given that gun violence is a leading cause of morbidity and mortality in the United States, place-based interventions that focus on improving the built environment should be central to public health policy. Epidemiologists working in public health agencies should be partnering with their local housing, code enforcement, and redevelopment authorities; mapping serious crime and gun violence; and assessing the role that each of these agencies can have in helping address the concentration of such problems in cities through place-based interventions that are within their purview.

Given that serious crime and gun violence are highly concentrated in the same places, strategic planning can have large-scale population health benefits. Imagine a scenario in which a thousand blocks in a city are responsible for 75% of all serious crime and gun violence. A set of place-based interventions could be launched, including redeveloping vacant lots, cleaning streets, improving sidewalks, and condemning abandoned structures for repurposing into new housing or businesses. If addressing the blighted built environment in this way produced a 30% reduction in serious crime and gun violence in these thousand blocks, the entire city would experience a 22.5% reduction in serious crime and gun violence.

In the United States, public health policy undervalues place-based interventions such as vacant lot repurposing and housing remediation as methods for reducing gun violence and serious crime. Although social programs have demonstrated promise in reducing serious crime, they are resource intensive and often hinge on a charismatic leader or a specialized programmatic model that is difficult to scale. Place-based interventions also require planning, overcoming inertia, and leadership, but they are easily scaled and achievable. The reality is that serious crime and gun violence are hyperconcentrated, suggesting that changes to the built environment could be a particularly salient non–criminal justice approach to prevention.