Characterizing Intent of Firearm Injuries by Number of Bullet Wounds

A complex and ongoing issue in firearm violence prevention research is correctly classifying injury intent (e.g., homicide, suicide, or unintentional). Emerging rule-based approaches to improve classification use the number of bullet wounds to infer intent of the injury when additional information is not available. Using the Centers for Disease Control and Prevention's National Violent Death Reporting System (NVDRS), which captures detailed information on intent of firearm injuries from coroner/medical examiner reports, law enforcement reports, and death certificates, this study examined potential evidence to support intent determination based on the number of bullet wounds.

2003-2021 NVDRS data on fatal firearm injuries was analyzed in 2023. ANOVA was used to test statistical significance of differences in average number of bullet wounds by intent, and Tukey's Honest Significant Difference Test was used to determine specific differences by intent.

A total of 299,362 fatal firearm injury decedents were identified. The average number of bullet wounds significantly differed by intent: suicide, 1.02; homicide, 2.72; and unintentional injury, 1.01 (p<0.01). Homicide decedents had a significantly higher average number of wounds than unintentional injury decedents and suicide decedents (ΔM homicide-unintentional injury [1.71; 95% CI=1.62, 1.79; p<0.01] and ΔM homicide-suicide [1.70; 95% CI=1.68, 1.72; p<0.01]).

The number of bullet wounds may be a useful indicator for classifying intent of firearm injuries, particularly for interpersonal assault, and when other supporting information is not available for medical coding. Accurate counts of firearm injuries by intent are critical for public health surveillance and prevention planning.