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Greening vacant lots to reduce violent crime: a randomised controlled trial
  1. Eugenia C Garvin1,
  2. Carolyn C Cannuscio2,
  3. Charles C Branas3
  1. 1Robert Wood Johnson Clinical Scholar, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
  2. 2VA Center for Health Equity Research and Promotion, Department of Family Medicine and Community Health, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
  3. 3Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
  1. Correspondence to Dr Eugenia C Garvin, Robert Wood Johnson Clinical Scholars, Perelman School of Medicine at the University of Pennsylvania, 13th Fl Blockley Hall, 423 Gaurdian Dr, Philadelphia, PA 19104, USA; eugenia.garvin{at}


Background Vacant lots are often overgrown with unwanted vegetation and filled with trash, making them attractive places to hide illegal guns, conduct illegal activities such as drug sales and prostitution, and engage in violent crime. There is some evidence that greening vacant lots is associated with reductions in violent crime.

Methods We performed a randomised controlled trial of vacant lot greening to test the impact of this intervention on police reported crime and residents' perceptions of safety and disorder. Greening consisted of cleaning the lots, planting grass and trees, and building a wooden fence around the perimeter. We randomly allocated two vacant lot clusters to the greening intervention or to the control status (no intervention). Administrative data were used to determine crime rates, and local resident interviews at baseline (n=29) and at follow-up (n=21) were used to assess perceptions of safety and disorder.

Results Unadjusted difference-in-differences estimates showed a non-significant decrease in the number of total crimes and gun assaults around greened vacant lots compared with control. People around the intervention vacant lots reported feeling significantly safer after greening compared with those living around control vacant lots (p<0.01).

Conclusions In this study, greening was associated with reductions in certain gun crimes and improvements in residents' perceptions of safety. A larger randomised controlled trial is needed to further investigate the link between vacant lot greening and violence reduction.

  • Vacant lots
  • greening
  • violence
  • crime
  • environment
  • urban planning
  • interventions
  • environmental modification
  • policy
  • public health
  • mechanism
  • firearm
  • helmet
  • alcohol/drugs
  • suicide
  • ems
  • homicide

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  • Funding This work was supported by a grant from the Robert Wood Johnson Health and Society Scholars Educational Fund (no grant number). The funders played no role in study design, data collection or data analysis.

  • Competing interests None.

  • Ethics approval Ethics approval was provided by the University of Pennsylvania Institutional Review Board.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement We are currently analysing data from the qualitative interview and walking interview of this study.