Table 3.
Negative Binomial Models: Incidence Rate Ratios of Mass Shootings in U.S. Counties
| MSA: Three or More Injuries | MSA: Four or More Deaths | |||
|---|---|---|---|---|
| MS2000–2009 = ∆ Covariates1990–2000 | MS2010–2015 = ∆ Covariates2000–2010 | MS2000–2009 = ∆ Covariates1990–2000 | MS2010–2015 = ∆ Covariates2000–2010 | |
| Adj. IRR (95% CI) | Adj. IRR (95% CI) | Adj. IRR (95% CI) | Adj. IRR (95% CI) | |
| Income inequality | 1.40 (1.05, 1.88) | 1.42 (1.17, 1.72) | 1.54 (1.12, 2.11) | 1.56 (1.12, 2.15) |
| Poverty rate | 0.82 (0.48, 1.38) | 2.10 (1.24, 3.55) | 0.66 (0.43, 1.00) | 1.87 (0.86, 4.08) |
| Unemployment rate | 0.85 (0.60, 1.22) | 1.10 (0.88, 1.37) | 0.94 (0.66, 1.34) | 0.99 (0.67, 1.47) |
| Population density | 0.31 (0.09, 1.05) | 0.05 (0.00, 0.57) | 0.24 (0.08, 0.67) | 0.72 (0.00, 0.93) |
| Young population | 0.75 (0.53, 1.07) | 3.10 (2.16, 4.44) | 0.83 (0.54, 1.28) | 2.68 (1.65, 4.35) |
| Minority population | 1.28 (0.12, 13.15) | 7.15 (3.07, 16.64) | 6.40 (1.01, 40.50) | 11.76 (3.78, 36.58) |
| HS graduation rate | 0.38 (0.21, 0.70) | 0.76 (0.51, 1.14) | 0.33 (0.21, 0.54) | 0.93 (0.65, 1.33) |
| Wald Chi-Square | 46.99 | 92.70 | 45.33 | 69.17 |
| County-Decades (N) | 3134 | 3139 | 3134 | 3139 |
Adj. IRR adjusted incidence rate ratio, CI confidence interval. All variables are logged and z-score standardized