Evaluating the impact of “stand your ground” self-defence laws in the US

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Funded by: Joyce Foundation

Start date: January 2019

End date: January 2021

Project outline

Since 2005, a series of controversial changes to self-defense laws have been enacted in a number of US states. These laws are known as “stand your ground” or “shoot first” laws, and they expand the rights of individuals to use lethal force in situations when a severe threat to their life is perceived. Advocates of these laws argue that they will result in positive effects on crime, deterring would be criminals. But there are growing concerns that these laws may have adverse effects on public safety.

This project will examine the impact of stand your ground laws across US states, aiming to examine and explain differences between states and population subgroups (e.g. different ages and racial groups). The project will employ a quasi-experimental design, using novel statistical methods to help understand the impact of these laws. The findings will be disseminated via international collaboration, research output(s), and public engagement.

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Co-principal Investigator: Douglas Wiebe (University of Pennsylvania, USA)

Co-investigator: Antonio Gasparrini (London School of Hygiene and Tropical Medicine, UK)

Humphreys DK, Gasparrini A, Wiebe DJ. Association Between Enactment of a ‘Stand Your Ground’ Self-defense Law and Unlawful Homicides in Florida. JAMA Intern Med 2017; 177: 1523–4.

Humphreys DK, Gasparrini A, Wiebe DJ. Evaluating the Impact of Florida’s ‘Stand Your Ground’ Self-defense Law on Homicide and Suicide by Firearm: An Interrupted Time Series Study. JAMA Intern Med 2017; 177: 44–50.

Ukert B, Wiebe DJ, Humphreys DK. Regional differences in the impact of the “Stand Your Ground” law in Florida. Preventive Medicine 2018; 115: 68–75.