Table 3. Effect Sizes of Within-State, Interstate, and Overall Associations Between State Firearm Laws and Firearm-Related Homicide and Suicide Ratesa,b.
| Firearm law | Within-state association | Interstate association | Overall association | |||
|---|---|---|---|---|---|---|
| Effect size (95% CI) | P value | Effect size (95% CI) | P value | Effect size (95% CI) | P value | |
| Firearm-related homicide | ||||||
| State firearm laws | ||||||
| Permit | −1.26 (−1.72 to −0.80) | <.001 | −9.01 (−15.00 to −3.02) | .003 | −10.27 (−16.53 to −4.01) | .001 |
| Relinquishment | −0.38 (−1.07 to 0.32) | .29 | 1.75 (−3.80 to 7.30) | .54 | 1.37 (−4.51 to 7.26) | .65 |
| Violence prohibition | 0.11 (−0.33 to 0.55) | .63 | 1.41 (−2.71 to 5.53) | .50 | 1.52 (−2.84 to 5.87) | .49 |
| Gun show | 0.06 (−0.47 to 0.60) | .82 | −4.75 (−9.81 to 0.31) | .07 | −4.69 (−9.91 to 0.53) | .08 |
| May-issue | −0.29 (−0.66 to 0.07) | .12 | −1.29 (−4.63 to 2.06) | .45 | −1.58 (−4.82 to 1.65) | .34 |
| Index of strictness of firearm regulationc | −0.03 (−0.17 to 0.12) | .72 | 0.00 (−0.03 to 0.03) | .89 | −0.03 (−0.19 to 0.13) | .72 |
| Firearm-related suicide | ||||||
| State firearm laws | ||||||
| Permit | −0.52 (−1.23 to 0.19) | .15 | −1.10 (−5.71 to 3.51) | .64 | −1.62 (−6.54 to 3.29) | .52 |
| Relinquishment | −0.44 (−0.94 to 0.06) | .08 | 3.02 (−0.37 to 6.41) | .08 | 2.58 (−1.10 to 6.26) | .17 |
| Violence prohibition | −0.86 (−1.23 to −0.50) | <.001 | −5.75 (−8.27 to −3.22) | <.001 | −6.61 (−9.28 to −3.95) | <.001 |
| Gun show | 0.03 (−0.27 to 0.32) | .85 | 0.91 (−1.86 to 3.69) | .52 | 0.94 (−1.85 to 3.74) | .51 |
| May-issue | 0.02 (−0.27 to 0.32) | .87 | 0.82 (−1.19 to 2.83) | .42 | 0.85 (−1.07 to 2.76) | .39 |
| Index of strictness of firearm regulationc | −0.07 (−0.14 to 0.00) | .06 | 0.01 (−0.01 to 0.03) | .23 | −0.06 (−0.12 to 0.00) | .07 |
a
Effect sizes are shown as per 100 000 population.
b
Models were adjusted for the following state-level time-varying variables: population size, proportion 65 years or older, race and ethnicity, unemployment rate, poverty rate, proportion 25 years or older without a high school diploma, the rates of crime against property, the percentage of state’s population holding a hunting license, number of licensed gun dealers per 100 000 residents, and the vote share difference between the Republican and Democratic candidates in the presidential election (linearly interpolated), in addition to state and year fixed effect.
c
Expressed as the decile of the total number of state firearm laws.