Effect of Remediating Blighted Vacant Land on Shootings: A Citywide Cluster Randomized Trial.

To determine if remediating blighted vacant urban land reduced firearm shooting incidents resulting in injury or death. We conducted a cluster randomized controlled trial in which we assigned 541 randomly selected vacant lots in Philadelphia, Pennsylvania, to 110 geographically contiguous clusters and randomly assigned these clusters to a greening intervention, a less-intensive mowing and trash cleanup intervention, or a no-intervention control condition. The random assignment to the trial occurred in April and June 2013 and lasted until March 2015. In a difference-in-differences analysis, we assessed whether the 2 treatment conditions relative to the control condition reduced firearm shootings around vacant lots. During the trial, both the greening intervention, -6.8% (95% confidence interval [CI] = -10.6%, -2.7%), and the mowing and trash cleanup intervention, -9.2% (95% CI = -13.2%, -4.8%), significantly reduced shootings. There was no evidence that the interventions displaced shootings into adjacent areas. Remediating vacant land with inexpensive, scalable methods, including greening or minimal mowing and trash cleanup, significantly reduced shootings that result in serious injury or death. Cities should experiment with place-based interventions to develop effective firearm violence-reduction strategies. This trial was registered with the International Standard Randomized Controlled Trial Number (study ID ISRCTN92582209; http://www.isrctn.com/ISRCTN92582209).