1. Across states, more guns = more unintentional firearm deaths

We analyzed data for 50 states over 19 years to investigate the relationship between gun prevalence and accidental gun deaths across different age groups. For every age group, where there are more guns, there are more accidental deaths. The mortality rate was 7 times higher in the four states with the most guns compared to the four states with the fewest guns.

Miller, Matthew; Azrael, Deborah; Hemenway, David. Firearm availability and unintentional firearm deaths. Accident Analysis and Prevention. 2001; 33:477-84.

2. Across states, unsafe gun storage = more unintentional firearm deaths

We analyzed data from the 2002 Behavioral Risk Factor Surveillance System that asked questions about guns and gun storage in the home, combined with information on deaths from the National Center for Health Statistics. Across states, both firearm prevalence AND questionable storage practices (i.e. storing firearms loaded and unlocked) were associated with higher rates of unintentional firearm deaths.

Miller, Matthew; Azrael, Deborah; Hemenway, David; Vriniotis, Mary. Firearm storage practices and rates of unintentional firearm deaths in the United States. Accident Analysis and Prevention. 2005; 37:661-67.

3. Youth killed in gun accidents are shot by other youth

The majority of people killed in firearm accidents are under age 24, and most of these young people are being shot by someone else, usually someone their own age. The shooter is typically a friend or family member, often an older brother. By contrast, older adults are at a far lower risk of accidental firearm death, and most often are shooting themselves. This article highlights one of the many benefits of the National Violent Death Reporting System (NVDRS). Before the NVDRS, data on the shooter in unintentional gun deaths was not readily available.

Hemenway, David; Barber, Catherine; Miller, Matthew. Unintentional firearm deaths: a comparison of other-inflicted and self-inflicted shootings. Accident Analysis & Prevention. 2010; 42:1184-8.