John MacDonald, Professor of Criminology and Sociology, University of Pennsylvania, presents, "Lessons Learned From a Citywide Abandoned Housing Experiment"

The negative impact of vacant and abandoned housing in city neighborhoods is extreme, affecting health and quality of life, promoting violence, and leading to further abandonment. One approach to addressing abandoned housing is to intervene with low-cost interventions that provide a visual sense of ownership. We tested whether a low-cost remediation of abandoned and vacant houses or a trash cleanup intervention would make a noticeable difference in the levels of nearby disrepair, disorder, and public safety. The abandoned housing remediation and trash cleanup interventions were a test of compliance with municipal ordinances. We used an experimental design to test the causal effects of the ordinances and because the scale of abandonment was too large to provide treatment to all abandoned houses in the city. We used systematic social observation methods to rate changes in disrepair, disorder, and litter at housing sites and on the city blocks they were located and police-reported data on gun violence and illegal substance use. Our experimental design allowed us to see whether observed disrepair, disorder, and public safety improved after working windows and doors were installed on abandoned houses compared with a trash cleanup around properties or a no-intervention control condition. Our results showed significant changes in observed disrepair, disorder, and gun violence and illustrate the benefits of experimental evaluations of place-based changes to the built environment.