U.S. County and State-Level Variability in Changes to Firearm Mortality Rates, 1989-2019

Firearm injuries caused 39,773 deaths in the United States (U.S.) in 2017, including 23,854 suicides, 14,542 homicides, and 486 unintentional injuries. Despite decreases in violent deaths in the 1990s, the rate of deaths from firearm injuries has increased in recent years. The firearm suicide rate increased from 6.7 per 100,000 population in 2014 to 7.3 per 100,000 in 2017, while the firearm homicide rate increased from 3.5 to 4.5 per 100,000 in the same period.[1] Firearms account for over 50% of suicides and two-thirds of homicides, making firearm injuries and deaths a critical public health challenge.[2] There is substantial state variation in rates of firearm fatalities and how these have changed over time. While time trends have been well characterized at the national and state level,[3] there is limited understanding about how firearm fatalities have changed at the finer spatial resolution of counties. Current understanding is thus restricted to the aggregated state level, which may obscure important variation in conditions that could contribute to discrepancies in firearm fatalities across the US. We propose to take an inductive and exploratory approach to this problem by using geographic “hotspotting” to benchmark US counties that are positive and negative outliers in changes in firearm mortality rates, including homicide, suicide, and unintentional deaths. We will then characterize outlier counties, rank states by average county-level changes, and investigate whether state firearm policies can explain changes over time. This proposed study thus aims to explain variability in changes to firearm mortality rates over time and identify future opportunities for intervention.