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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
To link to this article: http://dx.doi.org/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
E-mail: Mark.gius@quinnipiac.edu
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.
Keywords: assault weapons ban; mass shootings
JEL Classification: 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
attributes:
(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-profile public mass shootings that
fit this definition are Sandy Hook, Aurora, Fort
Hood, Virginia Tech and Columbine. Many of the
perpetrators in these mass shootings used multiple
types of firearms. Contrary to popular belief,
however, assault rifles 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 firearm in mass shoot-
ings (32.99% of mass shootings); rifles 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 2001–2010.
Even though rifles are used in less than 10% of
public mass shootings, one of the first 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 firearms 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
http://dx.doi.org/10.1080/13504851.2014.939367
©2014 Taylor & Francis 1
Downloaded by [Quinnipiac University], [M. P. Gius] at 06:57 14 August 2014
grips, flash 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
magazines.
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 fire 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 rifles could use
pre-ban large-capacity magazines. Given the above,
the federal law was limited in its ability to affect
firearm availability or crime.
Regarding state-level assault weapons bans,
California was the first state to enact such a law in
1989. Several other states followed California’s 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
significant 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 Australia’s 1996 gun
law reforms on firearm-related homicides, including
mass shootings, and found that, after enactment of the
laws, there were declines in firearm-related homicides
and suicides but no significant decrease in uninten-
tional firearm 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 ban’s
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-significant
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, fixed-
effect model and data for the period 1982 to 2011, it
was found that both state and federal assault weapons
bans had 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. 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
(1)
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 18–24;
2M. Gius
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percentage of population that is aged 25–34 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 1995–2004.
All data are state level and were collected for the
years 1982–2011. 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
Rifle 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 fixed-effect model, controlling
for both state-specific and year-specific 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 study’s 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-significant effects, but the
federal ban had a significant 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 rifle. In the same
year, there were 12 765 murders, of which only 322
were committed using a rifle. Rifles (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 rifles 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 fixed-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 fixed 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.
References
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) Australia’s
1996 Gun law reforms: faster falls in firearm deaths,
firearm suicides, and a decade without mass shoot-
ings, Injury Prevention,12, 365–72. doi:10.1136/
ip.2006.013714
Duwe, G., Kovandzic, T. and Moody, C. (2002) The
impact of right-to-carry concealed firearm laws on
mass public shootings, Homicide Studies,6, 271–96.
doi:10.1177/108876702237341
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,
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Huff-Corzine, L., McCutcheon, J., Corzine, J. et al.
(2014) Shooting for accuracy: comparing data
sources on mass murder, Homicide Studies,18,
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Koper, C. (2004) An Updated Assessment of the Federal
Assault Weapons Ban: Impacts on Gun Markets and
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Lott, J. and Landes, W. (2000) Multiple victim public
shootings, Unpublished Paper, University of
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