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The impact of state and federal assault weapons bans on public mass shootings



The purpose of the present study is to determine the effects of federal and state assault weapons bans on public mass shootings. Using a Poisson effect model and data for the period 1982 to 2011, it was found that both state and federal assault weapons bans have statistically significant and negative effects on mass shooting fatalities but that only the federal assault weapons ban had a negative effect on mass shooting injuries. This study is one of the first studies that looks solely at the effects of assault weapons bans on public mass shootings.
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Applied Economics Letters
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The impact of state and federal assault weapons bans
on public mass shootings
Mark Giusa
a Department of Economics, Quinnipiac University, Hamden, CT 06518, USA
Published online: 01 Aug 2014.
To cite this article: Mark Gius (2014): The impact of state and federal assault weapons bans on public mass shootings,
Applied Economics Letters, DOI: 10.1080/13504851.2014.939367
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The impact of state and federal
assault weapons bans on public
mass shootings
Mark Gius
Department of Economics, Quinnipiac University, Hamden,
CT 06518, USA
The purpose of the present study is to determine the effects of federal and
state assault weapons bans on public mass shootings. Using a Poisson
effect model and data for the period 1982 to 2011, it was found that both
state and federal assault weapons bans have statistically signicant and
negative effects on mass shooting fatalities but that only the federal assault
weapons ban had a negative effect on mass shooting injuries. This study is
one of the rst studies that looks solely at the effects of assault weapons
bans on public mass shootings.
Keywords: assault weapons ban; mass shootings
JEL Classication: K14; I12
I. Introduction
According to a recent report prepared by the
Congressional Research Service (Bjelopera et al.,
2013), a public mass shooting has four distinct
(1) Occurred in a relatively public place.
(2) Involved four or more deaths not including
the shooter.
(3) Victims were selected randomly.
(4) Shooting was not a means to a criminal end,
such as robbery or terrorism.
Examples of high-prole public mass shootings that
t this denition are Sandy Hook, Aurora, Fort
Hood, Virginia Tech and Columbine. Many of the
perpetrators in these mass shootings used multiple
types of rearms. Contrary to popular belief,
however, assault ries were not the predominant
type of weapon used in these types of crimes. In
fact, according to a recent study, handguns were the
most commonly used type of rearm in mass shoot-
ings (32.99% of mass shootings); ries were used in
only 8.25% of mass shootings (Huff-Corzine et al.,
2014). All data used in Huff-Corzine et al. (2014) is
for the period 20012010.
Even though ries are used in less than 10% of
public mass shootings, one of the rst pieces of
legislation that comes up for consideration whenever
there is a mass shooting is an assault weapons ban.
For example, after the Sandy Hook shooting, there
was a call for a revival of the 1994 federal assault
weapons ban. This rearms ban was part of the
Violent Crime Control and Law Enforcement Act
of 1994 and outlawed semi-automatic weapons that
had certain distinguishing features, such as pistol
Applied Economics Letters, 2014
©2014 Taylor & Francis 1
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grips, ash hiders and folding stocks (Koper, 2004).
The ban was very narrow; only 118 gun models were
banned under this law. In addition to banning certain
types of guns, the 1994 law also prohibited large-
capacity magazines, which held more than 10 rounds
of ammunition. This prohibition affected many more
types of guns than the assault weapons ban primarily
because many semi-automatic weapons, including
handguns, are capable of using large-capacity
The 1994 law had several loopholes and exemp-
tions. All assault weapons and large-capacity maga-
zines manufactured prior to the effective date of the
ban were legal to own and transfer. In addition, only
exact copies of the banned assault weapon models
were banned; models without certain characteristics
were still legal even though the rate of re was the
same. Finally, there was no prohibition against new,
legal assault weapons being able to accept older,
grandfathered large-capacity magazines. Hence,
most new, legal models of assault ries could use
pre-ban large-capacity magazines. Given the above,
the federal law was limited in its ability to affect
rearm availability or crime.
Regarding state-level assault weapons bans,
California was the rst state to enact such a law in
1989. Several other states followed Californias lead
and enacted their own bans shortly thereafter
(Connecticut, Hawaii and New Jersey), and then, in
1994, the federal ban was enacted. After the federal
ban expired in 2004, all of the states that had bans
prior to 1994 opted to continue with them.
Even though there have been numerous calls for
assault weapons bans, both at the state and at the
federal level, very little research has been conducted
on the effects of these laws on mass shootings. Gius
(2014), looking at data for the period 1980 to 2009,
found that state-level assault weapons bans had no
signicant effects on gun-related murderrates, but that
the federal assault weapons ban was associated with a
19% increase in gun-related murders. Chapman et al.
(2006) examined the effects of Australias 1996 gun
law reforms on rearm-related homicides, including
mass shootings, and found that, after enactment of the
laws, there were declines in rearm-related homicides
and suicides but no signicant decrease in uninten-
tional rearm deaths. It was also noted that there were
13 mass shooting incidents in Australia in the 18years
prior to the enactment of the stricter gun control
measures but no mass shootings after passage of the
laws. Koper (2004) looked at trends and correlations
and concluded that the federal assault weapons bans
effect on gun-related violence was minimal at best.
Duwe et al. (2002) examined the effects of right-to-
carry laws on mass shootings. Using data for the
period 1977 to 1999, the authors employed both
Poisson and negative binomial models and found
that right-to-carry laws had no statistically-signicant
effects on mass shootings. Finally, Lott and Landes
(2000) looked at mass shooting incidents also for the
period 1977 to 1997 and found that states that enacted
right-to-carry laws had fewer mass shootings than
states that did not enact such laws.
The purpose of the present study is to determine the
effects of the federal and state assault weapons bans
on public mass shootings. Using a Poisson, xed-
effect model and data for the period 1982 to 2011, it
was found that both state and federal assault weapons
bans had statistically signicant and negative effects
on mass shooting fatalities but that only the federal
assault weapons ban had a negative effect on mass
shooting injuries. This study is one of the rst studies
that looks solely at the effects of assault weapons bans
on public mass shootings. Most prior studies exam-
ined the effects of other types of gun control measures
on mass shootings (Lott and Landes, 2000; Duwe
et al.,2002;Chapmanet al.,2006) or the effects of
assault weapons bans on much broader categories of
crime (Koper, 2004;Gius,2014).
II. Empirical Technique and Data
In order to determine whether assault weapons bans
have any effects on public mass shootings, the fol-
lowing equation is estimated in the present study:
Y¼α0þα1state assault weapons ban
þα2federal assault weapons ban
þα3control variables
þα4state fixed effects
þα5year fixed effects
where Yis the number of deaths or injuries due to mass
shootings. Control variables include the following: per-
centage of population that is black; population density;
percentage of population that has a 4-year college
degree; per capita median income; annual unemploy-
ment rate; percentage of population that is aged 1824;
2M. Gius
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percentage of population that is aged 2534 and per
capita prison population. The state assault weapons ban
variable is expressed as a dummy variable that equals
one if the state has an assault weapons ban and zero
otherwise. The federal assault weapons ban dummy
variable equals one for the years 19952004.
All data are state level and were collected for the
years 19822011. Socio-economic data were
obtained from the Statistical Abstract of the United
States and other relevant Census Bureau documents.
Information on state-level assault weapons bans
were obtained from Ludwig and Cook (2003), the
Legal Community against Violence, the National
Rie Association and the US Bureau of Alcohol,
Tobacco, Firearms and Explosives.
Data on mass shootings were obtained from the
Mother Jones website and the Supplementary
Homicide Reports, US Department of Justice.
According to this data, there were 57 public mass
shooting incidents from 1982 to 2011. For the assault
weapons ban period (which includes the federal ban
years and the years when states that had their own
assault weapons bans), there were 24 public mass
shootings; for the nonban period, there were 33 inci-
dents. The average number of fatalities per mass
shooting during the assault ban period was 7.5; dur-
ing the nonban period, the average number of fatal-
ities was 8.6.
III. Results and Concluding Remarks
A Poisson, two-way xed-effect model, controlling
for both state-specic and year-specic effects, was
used to estimate the effects of state and federal
assault weapons bans on public mass shootings. All
observations were weighted by state population.
Results are presented on Table 1.
These results indicate that fatalities due to mass
shootings were lower during both the federal and
state assault weapons ban periods. Although some
prior research has shown either that assault weapons
bans did not reduce crime or that they actually
increased gun-related murder rates (Gius, 2014),
the present studys focus on mass shootings shows
the effectiveness of these gun control measures in
reducing murders due to mass shootings. Regarding
the injury regression, state-level assault weapons
bans had no statistically-signicant effects, but the
federal ban had a signicant and negative effect on
mass shooting injuries.
It is important to note that these results are not
unexpected. In 2012, for example, there were 72
fatalities due to mass public shootings. Of those 72,
at least 30 were committed using a rie. In the same
year, there were 12 765 murders, of which only 322
were committed using a rie. Ries (assault weap-
ons) are used much more frequently in mass shoot-
ings than they are in murders in general. Hence, any
law that restricts access to ries is likely to be much
more effective in reducing mass shootings than it is
in reducing murders in general.
Finally, it is important to note that mass shooting
fatalities are a very small percentage of overall mur-
ders. Hence, even if a certain type of gun control
measure was found to completely eliminate mass
shootings (which assault weapons bans do not), the
overall murder rate would decline by a very small
Table 1. Poisson xed-effects regression results
Variable Mass shooting deaths Mass shooting injuries
State assault weapons ban 0.59202 (2.28)** 0.298 (1.16)
Federal assault weapons ban 1.079 (7.04)*** 1.733 (10.10)***
Proportion of population that is black 65.66 (5.33)*** 87.05 (6.20)***
Population density 0.0177 (2.73)*** 0.0542 (7.18)***
Real per capita median income 0.000029 (0.48) 0.00021 (3.53)***
Proportion of population with college degree 1.66 (0.70) 4.72 (2.21)**
Unemployment rate 0.0698 (0.02) 3.51 (1.06)
Proportion of population >18 and <25 55.21 (5.94)*** 84.27 (7.81)***
Proportion of population >24 and <35 39.20 (5.09)*** 20.59 (2.65)***
Per capita prison population 0.00362 (4.62)*** 0.00067 (0.85)
Log-likelihood 1846.48 2860.63
Notes:**1%<p-value < 5%; *** p-value < 1%.
Test statistics are in parentheses.
State and year xed effects are not reported.
Assault weapons bans and mass shootings 3
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amount. Therefore, although the results of the present
study indicate that assault weapons bans are effective
in reducing mass shooting fatalities, their effects on
the overall murder rate are probably minimal at best.
Bjelopera, J., Bagalman, E., Caldwell, S. et al. (2013)
Public Mass Shootings in the United States:
Selected Implications for Federal Public Health
and Safety Policy, Congressional Research Service,
Washington, DC.
Chapman, S., Alpers, P., Agho, K. et al. (2006) Australias
1996 Gun law reforms: faster falls in rearm deaths,
rearm suicides, and a decade without mass shoot-
ings, Injury Prevention,12, 36572. doi:10.1136/
Duwe, G., Kovandzic, T. and Moody, C. (2002) The
impact of right-to-carry concealed rearm laws on
mass public shootings, Homicide Studies,6, 27196.
Gius, M. (2014) An examination of the effects of con-
cealed weapons laws and assault weapons bans on
state-level murder rates, Applied Economics Letters,
21, 2657. doi:10.1080/13504851.2013.854294
Huff-Corzine, L., McCutcheon, J., Corzine, J. et al.
(2014) Shooting for accuracy: comparing data
sources on mass murder, Homicide Studies,18,
10524. doi:10.1177/1088767913512205
Koper, C. (2004) An Updated Assessment of the Federal
Assault Weapons Ban: Impacts on Gun Markets and
Gun Violence, 19942003, Report to the National
Institute of Justice, US Department of Justice.
Lott, J. and Landes, W. (2000) Multiple victim public
shootings, Unpublished Paper, University of
Chicago Law School, Chicago, IL.
Ludwig, J. and Cook, P. (Eds) (2003) Evaluating Gun
Policy: Effects on Crime and Violence, The
Brookings Institution, Washington, DC.
4M. Gius
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... In 2015, Gius (2015) reported the results of the first study to examine the impact of state laws on mass shootings. He found that during the period 1982-2011, state-level assault weapons bans were associated with a significantly lower number of fatalities in mass shootings. ...
... For example, Gius (2015) classified Hawaii as having enacted an assault weapons ban in 1992. However, Hawaii's statute restricts only the sale of assault pistols; the law does not apply to assault rifles. ...
... Studies relying on the Supplementary Homicide Reports. At least three studies used the FBI's Supplementary Homicide Reports (SHR) as the main basis of their analyses, identifying those incidents in which four or more victims are fatally shot (Gius, 2015;Reeping et al., 2019;Webster et al., 2020). In addition to its limited range of variables, the SHR unfortunately presents a number of pitfalls for analytic efforts of this sort. ...
Objective: In this study, we analyzed the relationship between state firearm laws and the incidence and severity (i.e., number of victims) of mass public shootings in the United States during the period 1976-2018. Hypotheses: We hypothesized that states requiring permits to purchase firearms would have a lower incidence of mass public shootings than states not requiring permits. We also hypothesized that states banning large-capacity ammunition magazines would experience a lower number of victims in mass public shootings that did occur than states without bans. Method: We developed a panel of annual, state-specific data on firearm laws and mass public shooting events and victim counts. We used a generalized estimating equations logistic regression to examine the relationship between eight state firearm laws and the likelihood of a mass public shooting. We then used a zero-inflated negative binomial model to assess the relationship between these laws and the number of fatalities and nonfatal injuries in these incidents. Results: State laws requiring a permit to purchase a firearm were associated with 60% lower odds of a mass public shooting occurring (95% confidence interval [CI: -32%, -76%]). Large-capacity magazine bans were associated with 38% fewer fatalities (95% CI [-12%, -57%]) and 77% fewer nonfatal injuries (95% CI [-43%, -91%]) when a mass shooting occurred. Conclusion: Laws requiring permits to purchase a gun are associated with a lower incidence of mass public shootings, and bans on large capacity magazines are associated with fewer fatalities and nonfatal injuries when such events do occur. (PsycInfo Database Record (c) 2020 APA, all rights reserved).
... Using the negative binomial model on this more restrictive definition, they found that RTC laws had negative but insignificant effects on the number of incidents, the number killed, and the number wounded. Gius (2015) using Mother Jones and SHR data, estimated the effects of federal and state assault weapons bans for the years 1982-2011, finding evidence that such bans significantly reduced fatalities in mass shootings. Gius (2018) found that state assault weapon bans were associated with lower fatalities in school shootings. ...
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... One study examining mass public shootings found that over 85 percent of these deaths were attributable to assault rifles (DiMaggio et al. 2019). This same study also found that mass shooting-related fatalities were 70 percent lower during the 10-year period the FAWB was in effect, while a separate study (Gius 2015) determined that state-level assault weapons bans are similarly correlated with fewer deaths. ...
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... To the extent that violent crime is driven by economic inequality (Kelly, 2000;Vilalta et al., 2023), we construct a measure of state-level income inequality-the ratio of mean-to median in 2020-from 2020 US Census data. To control for the size of a state, we also use the state's population from 2020 US Census Data. 2 As our dependent variable of interest-the number of Mass Shootings in a state-is integer-valued, similar to Gius (2015), Klarevas et al. (2019), Kwon ...
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This paper considers the effects of firearms availability and adult mental health status on the number of mass shootings in a cross section of states in the US. We estimate the parameters of count data estimators, with and without zero inflation; with mass shooting counts from the gun violence archive, firearms availability data from the Bureau of Alcohol Tobacco and Firearms Federal Firearms Listing Data, and state-level individual adult mental health data from the Substance Abuse and Mental Health Data archive of the US Department of Health and Human Services. Parameter estimates reveal that the elasticity of mass shootings with respect to the adverse mental health status of adults is larger than the elasticity of firearms availability. This suggests that adult mental health is a relatively more important driver of mass shootings than firearms availability. Our findings on the relative elasticities of firearms availability and adult mental health status suggest that improving the mental health status of adults would be a powerful complement to policies reducing firearms availability in reducing the number of mass shootings across the US states.
... The evidence on specific gun control measures is mixed, however. For instance, whether assault weapon bans, an option strongly | 833 FACT-VALUEFRAMEWORKFORHEALTHPOLICYDEBATES favored by gun control advocates, would actually be effective at reducing mass shootings or gun violence more generally has been a matter of dispute, as well as how to define assault weapons (Gius, 2015(Gius, , 2018Siegel et al., 2019Siegel et al., , 2020. Recent studies have suggested that state gun laws restricting who has access to guns significantly reduces rates of firearm-related homicide more so than the type of gun that people may have access to (Siegel et al., 2020). ...
That policy should be evidence‐based has become a widely accepted dictum, especially in public health, where evidence‐based policy is strongly emphasized. Yet, most public health controversies arise because there is a conflict over values, which facts alone cannot resolve. Moreover, promoting population‐based health interventions requires the art of political actors to arouse public support. In discussing this tension in public health, studies often frame value conflicts as a barrier to rational decision‐making rather than viewing value considerations as an inherent part of democratic policymaking. We argue that by failing to engage value‐conflicts directly, public health professionals actually stymie evidence translation, which requires public and political buy‐in. We suggest a two‐by‐two framework that seeks to make value concerns more explicit in public health policymaking by breaking out policy controversies and alternatives along two dimensions—factual debates and value debates, creating four categories: uncontested alternatives, value debates, fact debates, and contested alternatives . We demonstrate that the policies that are most likely to be contested are those with a strong value conflict and where the evidence‐base is less solid. We also show that the framework is dynamic: fact and value conflicts are neither static nor inevitable. Rather, interested actors use both fact and value to try to push issues from contested to uncontested and vice‐versa. We conclude by demonstrating how the framework can help specify the role of both value and fact debates in public health policymaking through examples from U.S. public health policy controversies, including during the present COVID‐19 crisis.
... Not only has it been a persistent issue that has yet to be solved, but its malignant nature continues to make the cover of news headlines. It has proven to be such an issue that Agnich (2015) and Gius (2014) suggest school rampages have practically doubled since 1981. Further, 53% of the time, these shootings are found to be on K-12 campuses and are statistically the product of self-absorbed teenage boys who are outcasts and have a stout history of victimhood or who suffer from some sort of personal loss (Kimmel & Mahler, 2003). ...
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This report focuses on mass shootings and selected implications they have for federal policy in the areas of public health and safety. While such crimes most directly impact particular citizens in very specific communities, addressing these violent episodes involves officials at all levels of government and professionals from numerous disciplines. This report does not discuss gun control and does not systematically address the broader issue of gun violence. Also, it is not intended as an exhaustive review of federal programs addressing the issue of mass shootings.
Although researchers have questioned their coverage and accuracy, the media routinely are used as sources of data on mass murder in the United States. Databases compiled from media sources such as newspaper and network news programs include the New York Police Department's Active Shooters file, the Brady Campaign Mass Casualty Shootings data set, and the Mother Jones database. Conversely, official crime data have been underutilized by researchers who study mass murder (for exceptions, see Duwe, 2007; Fox & Levin, 1998). In this study, we compare similarities and differences for mass murder cases in the United States as portrayed by selected mass media sources. Then, we turn our focus to a comparison of the Uniform Crime Reports' (UCR) Supplementary Homicide Report (SHR) and the National Incident-Based Reporting System (NIBRS). Our primary focus is on mass murders involving four or more fatalities-not including the perpetrator-that have occurred between 2001 and 2010. Implications for enhancing the comprehensiveness and quality of mass murder data with the goal of increasing their usefulness for guiding prevention and risk mitigation efforts also are discussed.
Few events obtain the same instant worldwide news coverage as multiple victim public shootings. These crimes allow us to study the alternative methods used to kill a large number of people (e.g., shootings versus bombings), marginal deterrence and the severity of the crime, substitutability of penalties, private versus public methods of deterrence and incapacitation, and whether attacks produce "copycats." The criminals who commit these crimes are also fairly unusual, recent evidence suggests that about half of these criminals have received a "formal diagnosis of mental illness, often schizophrenia." Yet, economists have not studied multiple victim shootings. Using data that extends until 1999 and includes the recent public school shootings, our results are surprising and dramatic. While arrest or conviction rates and the death penalty reduce "normal" murder rates and these attacks lead to new calls from more gun control, our results find that the only policy factor to have a consistently significant influence on multiple victim public shootings is the passage of concealed handgun laws. We explain why public shootings are more sensitive than other violent crimes to concealed handguns, why the laws reduce the number of shootings and have an even greater effect on their severity.
Evaluating Gun Policy: Effects on Crime and Violence, The Brookings Institution
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