TABLE 2—
Results of Linear Regression Analyses for Homicides: Diadema, Brazil, January 1995–July 2005
| January and July 2000 Controlsa | No 2000 Intervention Controlsb | |||
| No Time Trend | Linear Time Trend | No Time Trend | Linear Time Trend | |
| Intercept, r (t) | −3.151*** (−9.762) | −4.510 (−0.036) | −2.876*** (−8.018) | 153.469** (2.788) |
| Linear time trend, years (t) | 0.001 (0.011) | −0.079** (−2.840) | ||
| January 2000 intervention, r (t) | −0.256 (−1.588) | −0.257 (−1.335) | ||
| July 2000 intervention, r (t) | −0.046 (−0.278) | −0.047 (−0.247) | ||
| Gun control law, r (t) | −0.541*** (−3.960) | −0.543** (−2.593) | −0.612*** (−3.934) | −0.351* (−2.231) |
| Unemployment rate, % (t) | 0.035* (1.802) | 0.035 (0.907) | 0.013 (0.622) | 0.071** (2.613) |
| New closing-time law, r (t) | −0.578*** (−4.937) | −0.579*** (−4.185) | −0.720*** (−6.027) | −0.504*** (−3.944) |
| ρ (t) | 0.245** (2.840) | 0.245** (2.842) | 0.337*** (4.022) | 0.234** (2.700) |
| Simulation of impact of new law | ||||
| Homicides prevented in 3 years, no. | 318.2 | 318.8 | 426.6 | 267.3 |
| Homicides prevented, % | 43.9 | 44.0 | 51.3 | 39.6 |
| 95% Lower bound on homicides prevented | 211.4 | 192.6 | 309.4 | 155.0 |
| 95% Upper bound on homicides prevented | 425.0 | 445.0 | 543.9 | 379.6 |
Note. Linear regression analyses related log-transformed homicide rates per 1000 population to untransformed exogenous measures using monthly data (N = 127 months). Models included generalized least squares correction for first-order autocorrelated residuals (Prais–Winsten estimator). The 2006 gun law and closing law interventions were coded as dummy variables.
aThe first 2 columns control for the 2002 previous enforcement changes. Within each of these pairs of columns, the first column does not control for underlying trends, whereas the second includes the linear time trend to control for unmeasured factors that may have influenced homicide rates.
bThe last 2 columns exclude controls for the 2002 previous enforcement changes. Within each of these pairs of columns, the first column does not control for underlying trends, whereas the second includes the linear time trend to control for unmeasured factors that may have influenced homicide rates.
* P < .05; **P < .01; ***P < .001 (2-tailed tests)