|
Abstract
|
BACKGROUND. Whether restricting access to handguns will reduce firearm-related homicides and suicides is currently a matter of intense debate. In 1976 the District of Columbia adopted a law that banned the purchase, sale, transfer, or possession of handguns by civilians. We evaluated the effect of implementing this law on the frequency of homicides and suicides. METHODS. Homicides and suicides committed from 1968 through 1987 were classified according to place of occurrence (within the District of Columbia or in adjacent metropolitan areas where the law did not apply), cause (homicide or suicide), mechanism of death (firearms or other means), and time of occurrence (before or after the implementation of the law). The number of suicides and homicides was calculated for each month during the study period, and differences between the mean monthly totals before and after the law went into effect were estimated. RESULTS. In Washington, D.C., the adoption of the gun-licensing law coincided with an abrupt decline in homicides by firearms (a reduction of 3.3 per month, or 25 percent) and suicides by firearms (reduction, 0.6 per month, or 23 percent). No similar reductions were observed in the number of homicides or suicides committed by other means, nor were there similar reductions in the adjacent metropolitan areas in Maryland and Virginia. There were also no increases in homicides or suicides by other methods, as would be expected if equally lethal means were substituted for handguns. CONCLUSIONS. Restrictive licensing of handguns was associated with a prompt decline in homicides and suicides by firearms in the District of Columbia. No such decline was observed for homicides or suicides in which guns were not used, and no decline was seen in adjacent metropolitan areas where restrictive licensing did not apply. Our data suggest that restrictions on access to guns in the District of Columbia prevented an average of 47 deaths each year after the law was implemented.
VioLit summary:
OBJECTIVE:
The purpose of this paper by Loftin et al. was to evaluate the effect of implementing a law that banned the purchase, sale, transfer, or possession of handguns by civilians, on the frequency of homicides and suicides in the District of Columbia.
METHODOLOGY:
A longitudinal study was used to compare the mean monthly numbers of gun-related homicides and suicides in the District of Columbia before the law was implemented with the numbers after its implementation. Comparisons using data of suicides and homicides committed in the district without firearms, homicides and suicides committed with firearms in adjacent metropolitan areas, and homicides and suicides committed without firearms in the adjacent metropolitan areas, was used to determine whether the observed differences were specific to the District of Columbia. Monthly totals of homicides and suicides were taken from the District of Columbia, Maryland, and Virginia during the period 1968 through 1987. The cases were classified according to place of occurrence, cause of death, mode of death, and month of occurrence. Four groups were defined for cause and mechanism of death in each case: homicide by firearms, homicide by other means, suicide by firearm, and suicide by other means. Unintentional deaths and deaths caused by firearms in which the intent was unknown were excluded for the monthly frequencies were too low for meaningful analysis. Eight separate 240-month time series were analyzed. As a check against possible effects of changes in the population, an analysis using mortality rates was also done using annual population estimates taken from the NCHS vital-statistics records for the years 1968 through 1987 using age group break downs of 5-19, 20-44, 45-64 years of age. A statistical inferences model was used to find that the difference between mean monthly rates of fatalities is an estimate of the magnitude of the intervention, and the statistical significance of the differences can be assessed with a t-test. Box and Tiao's methods was used for intervention analysis and are based on the autoregressive, integrated, moving average time-series models proposed by Box and Jenkins. The data was used to identify and estimate the appropriate models for within-series correlation. All analyses were conducted with use of algorithms in the SCA Statistical System software. All P values are two-tailed.
FINDINGS/DISCUSSION:
There was an abrupt decline in both suicides and homicides by firearms that coincided with the implementation of the restrictive licensing law. The reductions were specific to fatalities involving guns. In the District of Columbia, the mean frequency of both suicides and homicides by firearms declined by about one quarter in the period after the law went into effect. Gun related homicides, with a mean of 13.0 per month before the law was implemented, declined to a mean of 9.7 per month thereafter. Suicides with guns declined from a mean of 2.6 per month to 2.0 per month. The differences between the means before and after the law went into effect were statistically significant (P<0.001 for homicides and P=0.005 for suicides). None of the comparison time series showed declines of similar magnitude during the same period. Non-gun related homicides and non-gun related suicides in the District of Columbia declined only slightly (by 4% per month for homicides, and by 9% per month for suicides). These differences were not statistically significant. Both Maryland and Virginia, which did not have the change in gun regulation, did not have declines in gun-related homicides and suicides. The mean for gun-related homicides in these adjacent areas after the District of Columbia law was implemented was lower by 0.4 homicide per month (a decline of 7%), but the rate of suicides by guns was higher by 1.1 per month (an increase of 12%). Neither difference represents a statistically significant decline, but they provide additional evidence that the decline in fatalities was specific to suicides and homicides by firearms in the District of Columbia. The rates of both homicides and suicides by firearms declined in the period after the law went into effect (P<0.001 and P=0.085); at the same time, the rate of homicides committed by other means increased significantly (P=0.082) and suicides by other means did not change significantly.
AUTHORS' RECOMMENDATIONS:
The authors felt that though the data from the District of Columbia provided strong evidence that restrictive licensing of handguns reduced gun-related homicides and suicides, the data had limited usefulness in generalizing the data to other jurisdictions. Comparative studies of other gun-licensing laws would provide information on which to base wider generalizations and increase our understanding of the factors that influence the preventive effect of gun-licensing law.
EVALUATION:
This study adds support to the finding in gun-control research that strict legislation can decrease the fatalities from gun-related violence. The use of longitudinal design helps to support the causal connection between gun legislation and deaths by firearms while the comparison of Seattle and Vancouver assists in making this point. As the authors point out, there is weak generalizability from this research to other metropolitan areas in the United States both because of geographic specificity and potential cultural differences. There is clearly a need for more research; this study demonstrates that legislation probably would help to decrease the homicide/suicide problem. (CSPV Abstract - Copyright © 1992-2007 by the Center for the Study and Prevention of Violence, Institute of Behavioral Science, Regents of the University of Colorado)
N1 - Call Number: F-381, AB-381
KW - District of Columbia
KW - Firearms Trafficking
KW - Firearms Control
KW - Legislation
KW - Policy
KW - Homicide Prevention
KW - Death Rates
KW - Suicide Prevention
KW - Legislation Effects
Language: en |