Table 4 Zero-inflated negative binomial model describing the relationship between a state’s total number of firearm laws and number of other states for which it is the source of 50 or more crime-related firearms in a given year, adjusting for state-level characteristics, 2010–2017

Variable

b (95% CI)

Incidence Rate Ratio

Intercept

−0.62 (−0.96, −0.28)***

0.54

Year

0.09 (0.06, 0.13)***

1.10

Poverty rate

0.33 (0.20, 0.46)***

1.39

Density

−0.08 (−0.19, 0.04)

0.92

Area

0.21 (0.08, 0.35)**

1.24

Firearm ownership

−0.35 (−0.46, −0.25)***

0.70

Number of laws

−0.07 (−0.21, 0.08)

0.94

 New England

Ref

 Mid-Atlantic

1.96 (1.21, 2.71)***

7.08

 East North Central

2.19 (1.84, 2.53)***

8.93

 West North Central

0.90 (0.47,1.33)***

2.46

 South Atlantic

2.28 (1.89, 2.66)***

9.74

 East South Central

2.03 (1.62, 2.43)***

7.59

 West South Central

1.60 (1.15, 2.05)***

4.97

 Mountain

0.95 (0.56, 1.34)***

2.59

 Pacific

1.19 (0.77, 1.61)***

3.29

Variable

b (95% CI)

Adjusted Odds Ratio

Intercept

−10.05 (−1027.36, 1007.26)

4.32 × 10⁻⁰⁵