The Striking Relationship Between Gun Safety Laws and Firearm Deaths
Just this morning, the Senate Judiciary Committee approved a bill that would make it a federal crime to traffic guns (one of four gun control bills being discussed by the committee). This comes on the heels of an important new study published in JAMA Internal Medicine that documents the strong connection between stricter gun control laws and lower rates of gun deaths at the state level.
The study, by researchers at Boston Children's Hospital, Harvard Medical School, and Harvard School of Public Health, uses a measure of state-by-state "legislative strength" of gun control policies tracked by the Brady Center to Prevent Gun Violence, including measures to: (1) curb firearm trafficking; (2) strengthen background checks on purchasers of firearms beyond those required by the Brady Handgun Violence Prevention Act; (3) ensure child safety; (4) ban military style assault weapons; and (5) restrict guns in public places. It conducted a detailed statistical analysis (via a clustered Poisson regression) to examine the effect gun control laws on firearms fatalities.
The study found that states with the strictest gun control laws had lower rates of gun-related homicides and suicides, though it notes that these findings are limited to associations and could not determine precise cause-and-effect. Gun-related deaths were measured per 100,000 people for both homicides and suicides based on data from the Centers for Disease Control and Prevention, controlling for other factors thought to be associated with gun deaths including age, sex, race and ethnicity, poverty, unemployment, college education, population density, other violence-related deaths, and firearm ownership.
The map below, from the study, charts the mortality rate per 100,000 and legislative strength score. Louisiana had the highest rate of gun-related fatalities at 17.9 per 100,000, and Hawaii had the lowest at 2.9. Utah had the lowest legislative strength score of 0 and Massachusetts had the highest at 24.
The three scattergraphs below show the correlation between these data, legislative strength score to firearm deaths and ownership, as well as firearm deaths to firearm ownership.
Click for larger image
For the statisticians among you, here is how the study summarizes its main conclusions:
States in the highest quartile of legislative strength (scores of ≥9) had a lower overall firearm fatality rate than those in the lowest quartile (scores of ≤2) (absolute rate difference, 6.64 deaths/100 000/y; age-adjusted incident rate ratio [IRR], 0.58; 95% CI, 0.37-0.92). Compared with the quartile of states with the fewest laws, the quartile with the most laws had a lower firearm suicide rate (absolute rate difference, 6.25 deaths/100 000/y; IRR, 0.63; 95% CI, 0.48-0.83) and a lower firearm homicide rate (absolute rate difference, 0.40 deaths/100 000/y; IRR, 0.60; 95% CI, 0.38-0.95).