John MacDonald on Addressing Abandoned Housing to Improve Public Safety

John MacDonald's article, “Lessons Learned from a Citywide Abandoned Housing Experiment,” offers valuable insights into the relationship between the built environment and community wellbeing. This research, based on a randomized controlled trial (RCT), examines the effects of abandoned housing remediation on health and safety in urban neighborhoods. His findings have broad implications for urban development and strategic interventions aimed at improving communities.

The Problem of Abandoned Housing in Urban Areas

MacDonald's research focuses on the systematic remediation of abandoned housing, a major issue in many urban areas, particularly in regions like the Rust Belt. Abandoned homes are not just unsightly; they contribute to criminal activity, health risks, and social decline. The question, however, is whether interventions like demolitions or rehabilitations lead to meaningful improvements in safety and wellbeing or if they simply shift problems to other areas.

A Citywide Randomized Controlled Trial in Philadelphia

The study involved a citywide experiment that tested different interventions to address abandoned housing. Rather than being a passive observational study, it was designed to isolate the effects of remediation by comparing outcomes in treated areas to those in control areas. Researchers used systematic social observation (SSO) to gather reliable data on how the physical environment interacted with social dynamics, particularly regarding crime rates, public health, and community engagement.

Measurable Improvements in Safety and Public Health

The results of the RCT showed that remediating abandoned houses with working windows and doors significantly decreased observed disrepair, disorder, and gun violence, demonstrating the efficacy of experimental evaluations for place-based built environment interventions.

The study highlighted that improving compliance with Philadelphia ordinances to remediate abandoned housing could make a noticeable difference in disrepair in neighborhoods and contribute to improved public safety. 

Using AI to Monitor Built Environment Changes at Scale

MacDonald also emphasizes the potential for new technologies to enhance future research in this field. Artificial intelligence (AI) and machine learning could significantly expand the scope and depth of urban studies. AI presents a unique opportunity to scale up the systematic observation of social and environmental changes, using large-scale image data from satellite imagery, street-level photography, or even social media posts.

AI could be particularly useful for analyzing images that document changes in the built environment. By applying machine learning to these images, researchers could track urban interventions in real-time and identify patterns that traditional methods may miss. The ability to collect and analyze such data at scale would enhance our understanding of how urban changes affect residents' daily lives.

Connecting Built Environment Interventions to Community Outcomes

This work aligns with MacDonald's broader research focus areas, which center around how interventions in the built environment can improve community safety and health. These themes are also central to his coauthored book, Changing Places, which advocates for more strategic and evidence-based urban planning. The book emphasizes that while cities are constantly evolving, these changes often lack systematic evaluation to determine their impact on residents. By introducing data-driven techniques, such as AI-enhanced image analysis, urban planners could design and test more effective interventions that improve neighborhood conditions in the most economically disadvantaged communities.

Why Evaluating Urban Change Matters

MacDonald's research reminds us that altering the built environment is not just about aesthetics or economic growth; it is about improving lives. Unfortunately, renewal projects often lack the evaluation necessary to assess whether they genuinely improve safety and health. His work calls for a more thoughtful, data-driven approach to urban transformation, one that involves continuous monitoring to ensure that interventions are achieving their intended effects.

Dr. John MacDonald's work on abandoned housing remediation offers essential lessons for urban planners, policymakers, and researchers. His research shows that the built environment and social dynamics are closely interconnected, and that interventions must address both to be effective. By exploring the potential of AI and systematic data collection, MacDonald’s work lays the foundation for future studies that will explore how cities can be transformed to better serve residents, improving health, safety, and overall quality of life.

From Lessons Learned from a Citywide Abandoned Housing Experiment 

“An alternative response to vacant and abandoned housing is a set of interim policies that seek to keep building structures intact until properties are renovated and reoccupied. Cities like Chicago (IL) and Philadelphia (PA) passed municipal ordinances that required owners of vacant and abandoned properties to maintain exterior windows and doors in good condition. Planners should be interested in whether compliance with vacant property ordinances reduces visible signs of disorder, disrepair, and serious crime in communities, because vacant and abandoned properties are often the centers of criminal activity (Porter et al., 2019; Spelman, 1993; St. Jean, 2007)...

The evidence from prior research suggests that demolishing or renovating vacant and abandoned housing may reduce the level of illegal activity and violence in neighborhoods. The exact mechanisms through which demolishing or rehabilitating abandoned housing promotes these reductions is unclear. All published studies to date have been retrospective and relied on administrative data to assess the impact of housing demolition or rehabilitation programs on neighborhoods. Importantly, a major limitation of prior research is the lack of visual assessments of changes in physical disorder before and after changes to abandoned houses...

The concept of collective efficacy, or the willingness of residents to intervene in neighborhoods for the common good and out of shared mutual trust, suggests that a disordered built environment in a neighborhood may undermine social ties that foster informal social controls that mitigate criminal and antisocial behavior. For example, neighborhood residents may feel less empowered to intervene in the common good when there is no obvious owner maintaining a vacant and abandoned house and the property is left in a state of disrepair. Vacant and abandoned houses also signal that a site is not cared for and there is a “hole in the social fabric of a block” (Taylor, 1988, p. 186), potentially diminishing the perception that residents will act as guardians and intervene when they witness criminal activity in an area...

Our main findings from this experimental evaluation of compliance with the Philadelphia doors and windows ordinance have important implications for planners and policymakers confronting the legacy of vacant and abandoned houses in cities.

• Planning agencies should work with other city agencies to ensure that occupied residential blocks with vacant and abandoned houses have a remediation plan in place that includes low-cost treatments, such as the replacement of windows and doors in need of repair, façade cleaning, and regular trash removal.
• Remediating abandoned houses may help reduce the negative implications of physical disrepair on gun violence, an important indicator of public safety.
• Planners should pilot-test place-based changes to the built environment that can help economically disadvantaged communities abate problems of physical disorder that arise from vacant and blighted spaces.
• A research partnership between planners, community residents, local nonprofit service providers, and city agencies could help advance the science of place-based changes in a way that is useful for communities that have suffered from years of disinvestment...

Vacant and abandoned buildings pose significant challenges to the health, safety, and economic viability of neighborhoods. With our experiment, we sought to test the relative effectiveness of two abandoned building remediation interventions: the installation of working doors and windows and property maintenance through trash removal. By randomly assigning abandoned housing to receive functional doors and windows in place of missing or boarded-up ones, we tested the causal effect of the doors and windows ordinance relative to cleaning up trash in compliance with a property maintenance ordinance on litter and illegal dumping or a control condition that received no treatment. By relying on photo documentation, Google Street View, and SSOs, we visually assessed changes in disrepair, disorder, and litter around the houses that were part of this experiment as well as their surrounding block faces and the effect that visual changes to the built environment had on changes in gun violence and illegal substance use outcomes. 

The installation of working windows and doors led to a significant improvement in the appearance of disrepair of buildings but did not change ratings of surroundings or litter on block faces, suggesting that the intervention produced only a noticeable difference around the affected properties. The changes to the conditions of disrepair at housing sites appeared to contribute to significant relative reductions in gun violence outcomes, suggesting that remediating vacant and abandoned properties to a level that they appear occupied helped improve public safety.”