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Firearm Injury Interventions
Mandatory Sentencing
Background
One legislative strategy to reduce injuries
from guns is mandatory minimum or additional prison sentences for people convicted
of specified crimes while in possession of a firearm. These laws are based in the
hypothesis that, by decreasing the number of persons carrying firearms, the incidence
of firearm violence will decrease. One would expect that the laws would have their
greatest effects on shootings occurring in public places since these laws to not
address the issues of keeping firearms at home.
Many jurisdictions have passed such legislation.
Evaluations have appeared both in the criminology literature as well as in the public
health literature. Here, we review 6 such studies.
Review of mandatory sentencing legislation studies:
Author | O’Carroll et al., 1991 |
Study design and target population | Time series analysis. Population: Detroit, MI 1980-87. |
Intervention | 1986 city wide ordinance in Detroit, MI. Mandatory
jail sentence for concealing or carrying firearms. |
Outcomes | Incidence of firearm homicides outside and inside the
home. Evaluated all homicides, non-firearm homicides and in home homicides.
Use homicide records from Detroit Police Department. Analysis using time-series.
|
Results | There were significant increases in non-firearm homicides
(16%) and in homicides occurring in the home (22%) after the law compared to
before the law. In contrast, there were no significant increases in firearm
homicides (13%) and homicides outside the home (10%) after the law compared
to before the law. Ordinance not enforced largely because jails were full. |
Study quality and conclusions | The study appears to use valid data and employs ARIMA
modeling of time series for analysis.
The authors interpret the lack of a
statistically significant increase in firearm homicides and homicides outside
the home as showing an effect of the law since these were the target of the
law, and homicides inside the home and non-firearm homicides (both not targets
of the law) continued to increase. They ascribe the effect of the law to publicity
about it since it was not enforced. |
Author | Fife, 1989 |
Study design and target population | Interrupted time series over time period 1974-1986.
Population of New Jersey compared to the rest of the U.S. |
Intervention | Mandatory minimum prison sentence required for use
of firearm in a variety of crimes. Graves amendment, effective 1981.
definition of felony: crimes here murder, manslaughter,
aggravated assault, kidnapping, aggravated sexual assault, aggravated criminal
sexual assault, robbery, burglary, |
Outcomes | Percentage of homicides and suicides that involve firearms
over time. |
Results | Linear regression used to evaluate proportions of firearm
homicides 1974-80 vs 81-86 for N.J. compared to entire US. Overall 3.2% decrease
in proportion of firearm homicides in NJ.
No change in proportion of suicides due to
firearms in NJ, or for homicides in the rest of the US during the same time
period. |
Study quality and conclusions | Authors conclude mandatory sentencing reduced homicides
due to firearms.
Problems: simplistic analysis-no information
on incidence rates, no adjustment for confounding; secular trend for both
US and NJ shows proportion of firearm homicides dropped in later period; proportion
of firearm homicides much lower in NJ then rest of US |
Author | Loftin et al., 1983 |
Study design and target population | Interrupted time series study design; Detroit, Michigan |
Intervention | Michigan’s Felony Firearm Statute (implemented
Jan 1, 1977) required 2 year mandatory additional sentence for defendants convicted
of possession of a firearm during the commission of a felony.. Accompanying
publicity campaign about the law, "One will get you Two" |
Outcomes | Length of sentence by original charge, probability
of confinement if convicted, probability of conviction, & length of sentence
given confinement for Murder, armed robbery, felonious assault and 3 other felonies.
In addition, examined homicide, robbery, armed robbery and assault rates. |
Results | Law produced no changes in the length of sentence for
gun related crimes, the likelihood that persons convicted of violent gun-related
crimes would serve time except for felonious assaults. For these assaults, the
law may have reduced the likelihood of convicted, but increased the probability
and length of conviction.
No evidence of a discernible effect on the level or
pattern of violent crime in Detroit. |
Study quality and conclusions | No evidence that the law or the publicity campaign
which accompanied the law had any effect on violent crime. Law had very narrow
scope and penalty not strong enough to be a deterrent. |
Author | Loftin and McDowall, 1984 |
Study design and target population | Interrupted time series design. Population-3 cities
in Florida, Miami, Tampa, Jacksonville |
Intervention | Florida Felony Firearm Law effective 10/1/75 mandated
a 3 year sentence without parole for possession of firearm during commission
or attempted commission of 11 different felonies. |
Outcomes | Firearm homicide, armed robbery gun assault, non-gun
homicide, unarmed robbery, knife assault |
Results | Significant decrease in gun homicide found only in
Tampa but no reduction found in other two cities. Significant increase in gun
assaults in Tampa but no significant increase in other two cities. |
Study quality and conclusions | Little evidence that Florida gun law produced any systematic
decline in gun crimes in the 3 cities. Authors state scope of law is narrow,
applying only to individuals committing armed felonies; also, the additional
penalty is less than the felony sentence. |
Author | Lucas et al., 1978 |
Study design and target population | Before/after study design; patients treated for penetrating
wounds at Detroit General Hospital, Detroit, Michigan |
Intervention | Michigan’s Felony Firearm Statute . Required 2
year mandatory add on sentence for defendants convicted of possession of a firearm
in the commission of a felony. Passed Jan 1, 1977 |
Outcomes | Operations performed for firearm or knife wounds 6
months pre and post legislation. |
Results | 45% reduction in major surgeries for firearm wounds
compared to a 16% reduction for knife wounds. OR=0.63, 0.45-0.68 |
Study quality and conclusions | Authors conclude legislation responsible for drop in
surgery for firearm injuries. No changes in staffing for police, EMS, or in
hospital surgical procedures. Limitations: no control group. Comparisons over
very short time period; therefore, difficult to determine if sentencing guidelines
caused change. |
Summary of mandatory sentencing legislation studies
The data available at present give conflicting results as the effectiveness of
such laws in decreasing firearm related violent injuries. The analyses are necessarily
complex to take into account secular changes in rates of violent crime and firearm
related injuries However, these analyses at present only adjust for secular changes
and colinearity, but nothing else. There are potential threats to the validity of
time series analyses such as other laws, societal changes, and other policies which
can influence crime.
Recommendations on mandatory sentencing
At present, the conflicting data, all based on time series analyses, do not allow
us to recommend these laws as a strategy which will have a definite effect on injury
rates. There may, however, be other compelling reasons to enact such laws.
Recommendations for future research
McDowall and colleagues10
in 1995 made a good attempt to evaluate shall
carry/concealed weapons laws. In 1995 additional states adopted legislation making
it easier to obtain concealed weapons permits. These effect of these laws should be
evaluated using Poisson regression and time series analyses in order to determine
their effect.
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