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Increasing adolescent firearm homicides and racial disparities following Florida’s ‘Stand Your Ground’ self-defence law
  1. Michelle Degli Esposti1,
  2. Douglas J Wiebe2,
  3. Jason Gravel2,
  4. David K Humphreys1
  1. 1 Social Policy and Intervention, University of Oxford, Oxford, UK
  2. 2 Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
  1. Correspondence to Dr Michelle Degli Esposti, Social Policy and Intervention, University of Oxford, Oxford OX1 2ER, UK; mdesposti{at}


Establishing whether specific laws impact rates of firearm homicide in adolescents is critical for identifying opportunities to reduce preventable adolescent death. We evaluated Florida’s Stand Your Ground law, enacted October 2005, using an interrupted time series design from 1999 to 2017. We used segmented quasi-Poisson regression to model underlying trends in quarterly rates of adolescent (15–19 years) firearm homicide in Florida and disaggregated by race (Black/White). We used synthetic and negative controls (firearm suicide) to address time-varying confounding. Before Florida’s Stand Your Ground law, the mean quarterly rate was 1.53 firearm homicides per 100 000 adolescents. Black adolescents comprised 63.5% of all adolescent firearm homicides before and 71.8% after the law. After adjusting for trends, the law was associated with a 44.6% increase in adolescent firearm homicide. Our analysis indicates that Florida’s Stand Your Ground is associated with a significant increase in firearm homicide and may also exacerbate racial disparities.

  • time series
  • behaviour change
  • public health
  • legal intervention
  • adolescent

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  • Contributors MDE contributed to the conceptualisation and design of the study, statistical analyses, interpretation of data, drafting of the article, and review and revision of the article. DJW, JG and DKH critically reviewed and revised the article.

  • Funding This study was funded by Joyce Foundation.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval Full ethics review was not applicable but we still sought, and were granted: Departmental Research Ethics Committee approval: SPI_DREC_18_020.

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