Impulse Purchases, Gun Ownership, and Homicides: Evidence from a Firearm Demand
Shock1
Christoph Koenig2
David Schindler3
Juli 23, 2021
Abstrakt: Do firearm purchase delay laws reduce aggregate homicide levels? Using
variation from a 6-month countrywide gun demand shock in 2012/2013, we show that
UNS. states with legislation preventing immediate handgun purchases experienced smaller
increases in handgun sales. Our findings indicate that this is likely driven by compar-
atively lower purchases among impulsive consumers. We then demonstrate that states
with purchase delays also witnessed comparatively 2% lower homicide rates during the
1This paper supersedes a previous version entitled “Dynamics in Gun Ownership
and Crime — Evidence from the Aftermath of Sandy Hook”. We thank participants
of numerous seminars and conferences for feedback. The paper benefited from helpful
comments by Bocar Ba, Sascha O. Becker, Aaron Chalfin, Amanda Chuan, Florian
Englmaier, Stephan Heblich, Alessandro Iaria, Judd Kessler, Martin Kocher, Botond
K˝oszegi, Florentin Kr¨amer, Katherine Milkman, Takeshi Murooka, Emily Owens, Arnaud
Philippe, Alex Rees-Jones, Marco Schwarz, Simeon Schudy, Peter Schwardmann, Hans H.
Sievertsen, Lisa Spantig, Uwe Sunde, Ben Vollaard, Fabian Waldinger, Mark Westcott,
Julia Wirtz, Daniel Wissmann, Noam Yuchtman and, insbesondere, Yanos Zylberberg.
The comments of Shachar Kariv and three referees substantially improved an earlier
Entwurf. David Schindler would like to thank the Department of Business Economics &
Public Policy at The Wharton School, where parts of this paper were written, for its
hospitality.
2University of Bristol & CAGE. Email: Christoph.Koenig@bristol.ac.uk
3Korrespondierender Autor, d.schindler@tilburguniversity.edu, Tilburg University
& CESifo Munich.
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0110621Review of Economics and Statistics Just Accepted MS.restby the President and Fellows of Harvard College and the Massachusetts Institute of Technology. Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) Lizenz.
same period. Further evidence shows that lower handgun sales coincided primarily with
fewer impulsive assaults and points towards reduced acts of domestic violence.
JEL-Codes: K42, H76, H10, K14
Schlüsselwörter: Waffen, homicides, gun control
1 Einführung
The relationship between firearm ownership and criminal activity has been one of the
most polarizing topics in U.S. politics over the past decades. Supporters of gun rights
often claim that arming citizens will lead to decreases in crime, while supporters of gun
control point to the high numbers of victims of gun-related violence. Fowler et al. (2015)
report that 32,000 Americans are killed and another 67,000 injured by firearms every
Jahr. Based on their calculations, any policy measure effectively reducing these numbers
would thus have the potential for welfare gains of almost $50 billion each year. Curbing gun violence was also the intention behind many of the 130 gun control policy measures that have been enacted so far across U.S. Staaten (Siegel et al., 2017). One such group of policy measures, targeted explicitly at preventing impulsive acts of gun violence, are firearm purchase delay laws. These measures, by now in place in 15 UNS. Staaten, create a temporal distance between the decision to buy a gun and its eventual receipt. Delays can last from 2 days up to 6 months and occur through mandatory waiting periods or bureaucratic hurdles associated with obtaining purchasing permits. Both measures provide gun buyers with a “cooling-off period” during which those with short- lived suicidal or homicidal intentions may reconsider their planned actions (Cook, 1978; Andr´es and Hempstead, 2011). Since delay laws should also keep impulsive consumers without violent intentions from buying guns, they offer a unique avenue to investigate whether and how prevented firearm purchases by such individuals translate into reduced 2 l D o w n o a d e d von h t t p : / / Direkte . m i t . e du / r e s t / l a r t i c e – p d f / d o i / . / 1 0 1 1 6 2 / r e s t _ a _ 0 1 1 0 6 1 9 6 6 3 2 4 / r e s t _ a _ 0 1 1 0 6 p d . f by gu e s t o n 0 8 S e p e m b e r 2 0 2 3 0110621Review of Economics and Statistics Just Accepted MS.restby the President and Fellows of Harvard College and the Massachusetts Institute of Technology . Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) Lizenz. gun violence. Jedoch, such analysis would require a reasonably large shift in impulse purchases unrelated to local crime levels. In diesem Papier, we exploit one of the largest aggregate shocks to U.S. firearm demand to study the effects of handgun purchase delay laws. In a first step, we show that the existence of purchase delays led to a relative reduction in handgun sales during the six months after the 2012 Presidential election and the shooting at Sandy Hook Elementary School. Während dieser Zeit, fear of more restrictive gun control legislation and higher perceived need for self-defense capabilities led to record sales of firearms across the entire United States (Vox, 2016; CNBC, 2012). We use a difference in differences (DiD) Rahmen, comparing handgun sale background checks (BGCs) in states with handgun purchase delays to states without such delays during the six-month window of increased firearm demand. Our baseline results indicate that states with purchase delay laws witnessed a 7-8% relative decrease in handgun sales. Differences in gun popularity and other types of firearm legislation cannot explain these results. Nächste, we present evidence suggesting that lower purchasing levels were indeed more likely driven by impulsive buyers. We start by analyzing Google search data and show that delay laws did not lead to comparatively lower public interest in buying firearms during the demand shock. Handgun purchase delay laws thus did not seem to affect intentions to buy firearms, but only whether consumers’ interest translated into actual purchases. Using state variation in delay lengths, we also do not observe a relationship between our estimated effect size and delay length. For deliberate and exponentially discounting consumers, these should have been positively correlated since delays smoothly reduce the discounted net present value of owning a gun. This discontinuous impact of delay lengths on purchases lends further credibility to the presence of impulsive consumers. 3 l D o w n o a d e d von h t t p : / / Direkte . m i t . e du / r e s t / l a r t i c e – p d f / d o i / / . 1 0 1 1 6 2 / r e s t _ a _ 0 1 1 0 6 1 9 6 6 3 2 4 / r e s t _ a _ 0 1 1 0 6 p d . f by gu e s t o n 0 8 S e p e m b e r 2 0 2 3 0110621Review of Economics and Statistics Just Accepted MS.restby the President and Fellows of Harvard College and the Massachusetts Institute of Technology . Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) Lizenz. In the second part of our analysis, we investigate the effect of delay laws on homicides. Using the same DiD framework, we find that counties in states with purchasing delays experienced a relative 2% decrease in overall homicide rates during the demand spike, which is entirely driven by homicides involving handguns. Our baseline estimate implies that about 200 lives could have been saved in the six-month period alone if handgun purchase delays had been in place in all U.S. Staaten. An extensive set of robustness checks shows that our results are specific to the period of the demand hike and not driven by single states or the sample choice. Looking into the characteristics of the additional homicides in states without handgun purchase delays, we find evidence in line with the notion that gun ownership among impulsive buyers is associated with crimes of passion. 4 For female victims, the evidence points towards instances of domestic violence, as the majority of additional female homicides occurred inside the victim’s home and arose from an argument. The affected killings of males occurred mainly outside of their homes but were similarly strongly related to arguments. This study is related to three important streams of research. Erste, we add to the literature investigating the impact of firearm legislation, and in particular purchase delays, on crime rates. Previous studies found either decreases (Rudolph et al., 2015; Edwards et al., 2018; Luca, Malhotra, and Poliquin, 2017) or zero effects (Ludwig and Cook, 2000) on violent crime or homicides. As the adoption of firearm purchase delay laws may not be exogenous and law changes can be anticipated by prospective gun buyers, our paper substantially advances this literature by providing novel and credible identification through exploiting a sudden and unanticipated demand shock in conjunction with pre- 4All statements regarding a relative increase in handgun sales and homicides in states without handgun purchase delays are just the flip side of the relative decrease in handgun sales and homicides in states with such delays. 4 l D o w n o a d e d von h t t p : / / Direkte . m i t . e du / r e s t / l a r t i c e – p d f / d o i / / . 1 0 1 1 6 2 / r e s t _ a _ 0 1 1 0 6 1 9 6 6 3 2 4 / r e s t _ a _ 0 1 1 0 6 p d . f by gu e s t o n 0 8 S e p e m b e r 2 0 2 3 0110621Review of Economics and Statistics Just Accepted MS.restby the President and Fellows of Harvard College and the Massachusetts Institute of Technology . Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) Lizenz. existing delay laws.5 We also provide suggestive evidence that our empirical setup mainly picks up the behavior of impulsive consumers without violent intentions and offers insights into the types of homicides prevented through purchase delays. Zweite, we contribute to the extant literature in economics, criminology, and public health, studying the impact of firearm ownership on violent crime. The majority of studies find a positive relationship (sehen, z.B., Cook and Ludwig, 2006; Duggan, 2001; Müller, Azrael, and Hemenway, 2002; Müller, Hemenway, and Azrael, 2007; Siegel, Ross, and King, 2013). Some studies, Jedoch, also report no effect (Duggan, Hjalmarsson, and Jacob, 2011; Moody and Marvell, 2005; Kovandzic, Schaffer, and Kleck, 2013; Lang, 2016). A recent paper by Levine and McKnight (2017) shows with a different identification strategy that elevated gun exposure after the Sandy Hook shooting translated into higher rates of firearm-related accidents.6 We confirm the positive link between gun ownership and homicides found in previous studies but are the first to look specifically into firearm homicide characteristics and highlight the role of impulsiveness. Dritte, our evaluation of gun purchase delay laws contributes to the growing literature analyzing how policies can mitigate the consequences of behavioral biases (overviews are provided in Chetty, 2015; Bernheim and Taubinsky, 2018). To the best of our knowledge, we are the first to study impulsive behavior in the context of gun ownership. Few other studies at the intersection between behavioral economics and economics of crime have 5The identification strategy of overlaying cross-sectional variation in pre-existing characteristics with a common time-series shock has also been applied in other work (sehen, z.B., Nunn and Qian (2011). 6While gun-related accidents are not at the heart of our paper, supplementary results reported in the Appendix based on our own identification strategy cannot replicate those findings. Our main results suggest that the primary detrimental effect of increased gun ownership after the Sandy Hook shooting was an increase in gun-related homicides. 5 l D o w n o a d e d von h t t p : / / Direkte . m i t . e du / r e s t / l a r t i c e – p d f / d o i / . / 1 0 1 1 6 2 / r e s t _ a _ 0 1 1 0 6 1 9 6 6 3 2 4 / r e s t _ a _ 0 1 1 0 6 p d . f by gu e s t o n 0 8 S e p e m b e r 2 0 2 3 0110621Review of Economics and Statistics Just Accepted MS.restby the President and Fellows of Harvard College and the Massachusetts Institute of Technology . Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) Lizenz. also linked impulsiveness to criminal activity and acts of violence (Dahl and DellaVigna, 2009; Card and Dahl, 2011; Heller et al., 2017). We advance this literature by providing the first study to establish a link between firearm availability and the fatal consequences of impulsive behavior. 2 Hintergrund 2.1 Purchase Delay Laws in the United States The Second Amendment to the United States Constitution protects the fundamental right of citizens to keep and bear arms. Federal, state, and local governments, Jedoch, have enacted laws making it harder and more cumbersome for citizens to acquire firearms. On the federal level, two crucial pieces of legislation are the Gun Control Act of 1968 and the Brady Handgun Violence Prevention Act. The Gun Control Act requires all professional gun dealers to have a Federal Firearms License (FFL). Only they can engage in inter-state trade of handguns, are granted access to firearm wholesalers, and can receive firearms by mail. The Brady Act of November 1993 mandated BGCs for all gun purchases through FFL dealers and imposed a five-day waiting period to conduct these checks. Upon successful lobbying by the National Rifle Association (NRA), these waiting periods were set to expire when the FBI’s National Instant Criminal Background Check System (NICS) was introduced in 1998. Since then, the NICS handles all BGCs related to the sales of firearms. While there is comparatively little regulation on gun ownership at the federal level, there is substantial heterogeneity in restrictions imposed by U.S. Staaten. Constraints on private firearm ownership at the state level predominantly attempt to either prohibit potentially dangerous people such as convicted felons from acquiring guns or restrict the usefulness of firearms for unlawful purposes independent of the buyer. 6 l D o w n o a d e d von h t t p : / / Direkte . m i t . e du / r e s t / l a r t i c e – p d f / d o i / . / 1 0 1 1 6 2 / r e s t _ a _ 0 1 1 0 6 1 9 6 6 3 2 4 / r e s t _ a _ 0 1 1 0 6 p d . f by gu e s t o n 0 8 S e p e m b e r 2 0 2 3 0110621Review of Economics and Statistics Just Accepted MS.restby the President and Fellows of Harvard College and the Massachusetts Institute of Technology . Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) Lizenz. In this study, we focus on handguns since these, unlike long guns, have to be purchased in the state of residence, are a popular choice for self-defense, can be carried concealed, and are used in homicides substantially more often than long guns (Federal Bureau of Investigation, 2016). Our analyses utilize two types of delays between the decision to purchase and the moment the handgun is actually transferred. The first one is mandatory waiting periods. While the initial aim of waiting periods in the Brady Act was to give law enforcement agencies enough time to conduct BGCs, they also provide a “cooling-off” period and can thus help to prevent impulsive acts of violence (Cook, 1978; Andr´es and Hempstead, 2011). In der Praxis, buyers will perform a purchase (pass a NICS BGC and pay for the chosen gun) but can only receive their handgun after the waiting period has elapsed. The second measure is state requirements for licenses to lawfully possess or buy a handgun. Due to bureaucratic hurdles in the licensing process, these impose a de-facto waiting time. Prospective buyers have to request the permit at a local authority (z.B., a sheriff’s office), pass a NICS BGC, and pay the associated fee.7 Only after the permit has been processed and issued can they proceed with the purchase at their local dealer (usually without a renewed BGC). In order to accurately determine the presence of delay laws and minimize misclas- sification, we utilize several sources and apply a rigorous coding procedure outlined with all details in Appendix Section A.1. The final state classification is reported in Appendix Table 27, which shows that during the period of our study, from November 2009 bis Oktober 2013, 15 states and the District of Columbia had adopted some form of delay laws throughout. Nine states (Kalifornien, Florida, Hawaii, Illinois, Maryland, Minnesota, New Jersey, Rhode Island, Wisconsin) and the District of Columbia had 7Fees can range from $1 plus notary fee in Michigan to $340 in New York City ($100
in the state of New York). Siehe https://www.cga.ct.gov/2013/rpt/2013-R-0048.htm.
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imposed mandatory waiting periods on handgun purchases.8 Connecticut, Hawaii, Illinois,
Maryland, Massachusetts, New Jersey, New York, Nebraska, North Carolina, and Rhode
Island all require a purchasing permit during the period of our study. Michigan abolished
its handgun permit requirement in December 2012 and is thus the only state switching
its delay legislation during our study period. For the remainder of this paper, we will
refer to a state which implemented a mandatory waiting period, required a purchasing
permit, oder beides, as a Delay state.9 We refer to all other states as NoDelay states.
2.2 The Firearm Demand Shock of 2012/2013
Our analysis focuses on the firearm demand spike after the re-election of President Obama
in November 2012 and the Sandy Hook shooting in December 2012. We decided on these
two particular events to study the impact of delay laws on gun sales and homicides for
two main reasons: Zuerst, these events then marked the largest hike in handgun sales since
background data was collected in 1999. Such a strong shock is required in order to detect
any statistically significant effects on firearm purchases and homicides. Zweitens, nicht wie
the numerous later shootings that grabbed nationwide attention, our setup features a
pre-treatment period uncontaminated by other events, which is essential to accurately
account for the seasonal nature of the data. Im Folgenden, we briefly describe the two
events and the firearm demand hike of 2012/2013.
In the Presidential Election on 6 November 2012, President Barack Obama ran for
a second term against Republican candidate Mitt Romney. While Romney took a more
8Wisconsin repealed its 48-hour handgun waiting period in only 2015 and is thus part
of our sample.
9For purchasing permits, Tisch 27 states the maximum delay allowed by law. Dort
is no reliable information on average delays that we are aware of. As we binarize the
treatment, averaging would be inconsequential for our analysis.
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liberal position towards gun rights and was endorsed by the NRA, President Obama
favored stricter gun control laws. In October 2012, almost all polls showed the race as
within the margin of error, and President Obama’s victory came so unexpectedly for
Romney on election night that he had not even prepared a concession speech as internal
polls had shown him winning (International Business Times, 2012). Similar to President
Obama’s first election in 2008, gun sales increased after his re-election, but this time with
considerably larger magnitude (CNN, 2008; CNN Money, 2012; Depetris-Chauvin, 2015).
This was likely because the President had started to speak more openly about favoring
increased gun control measures in the wake of recent mass shootings, especially the one
at a movie theater in Aurora, Colorado, in July 2012.
About a month later, An 14 Dezember 2012, then 20-year-old Adam Lanza of Newtown,
Connecticut first shot and killed his mother at their home before driving to Sandy Hook
Elementary School. There he shot and killed six school employees and 20 students aged
six to seven years. Lanza committed suicide shortly after the first law enforcement officers
arrived at the scene. His motives are still not fully understood, but it has been suggested
that he had a history of mental illness (New Yorker, 2014). The massacre was the deadliest
ever U.S. school shooting and the third deadliest mass shooting in U.S. history at the
Zeit. This and the fact that most of the victims were defenseless children sparked a
renewed and unprecedented debate about gun control in the United States.
A few days after the shooting, President Barack Obama announced that he would
make gun control a central issue of his second term and quickly assembled a gun violence
task force led by then-Vice President Joe Biden to collect ideas on how to curb gun
violence and prevent future mass shootings. The task force presented their suggestions
to President Obama in January 2013, who announced to implement 23 executive actions.
These were aimed at expanding BGCs, addressing mental health issues and insurance
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coverage of treatment, as well as enhancing safety measures for schools and law en-
forcement officers responding to active shooter situations. Zusätzlich, the task force
proposed twelve congressional actions, including renewing the Federal Assault Weapons
Ban, expanding criminal BGCs to private transactions, banning high-capacity magazines,
and increasing funds for law enforcement agencies.
The proposals were met by fierce opposition from the NRA and some Republican
legislators. At the end of January 2013, Senator Dianne Feinstein introduced a bill to
reinstate the Federal Assault Weapons Ban. While the bill passed the Senate Judiciary
Committee in March 2013, it eventually was struck down on 17 April 2013 by the Senate
40-60 with all but one Republican and some Democrats opposing the bill. A bipartisan
bill to be voted on that same day, introduced by Senators Joe Manchin and Pat Toomey,
aimed at introducing universal BGCs, also failed to find the necessary three-fifths majority
mit 54-46, leaving federal legislation eventually unaffected.
Even though no new federal regulations followed, gun sales soared further in the
months after the Sandy Hook shooting. Fear of stricter gun legislation and a higher
perceived need for self-protection drove up sales for both handguns and rifles (Vox,
2016). While gun sales had surged after every prior mass shooting during the Obama
administration, the surge after the shooting at Sandy Hook was unprecedented. Der
extreme demand shift even created supply problems for some dealers while others were
hoping for sales increases of a magnitude of up to 400% (CNBC, 2012; Huffington Post,
2013). Several executives in the gun industry have stated that they view mass shootings
as a boon to their business, attracting especially first-time gun owners (The Intercept,
2015). In line with these anecdotes, Figur 1 shows a clear spike in gun sales starting in
November/December 2012 after the Presidential election and the Sandy Hook shooting.
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While gun sales generally increase at the end of the year, this particular spike is far more
pronounced and prolonged than in the years immediately before and after.
FIGURE 1 ABOUT HERE
3 Data
3.1 Handgun Purchases
One of the main challenges in our analysis is the absence of a central database of gun
owners and firearm sales. To overcome this, researchers have often turned to proxy
variables from surveys, vital statistics, crime data, and gun magazine subscriptions.
While some of these indicators performed well in cross-sectional analyses, they have been
found unsuitable for tracking gun ownership over time (Kleck, 2004). Since Novem-
ber 1998, Federal law dictates that an electronic NICS BGC be carried out for every
firearm transaction through an FFL dealer. This publicly available data has the merit
of being comparable across time, providing high coverage at a monthly frequency, Und
distinguishes between different types of transactions and firearms. The main variable in
the first part of our analysis is NICS BGCs for handgun sales in a given state between
November 2010 und Oktober 2013, divided by the 2010 population in 100,000. In order to
interpret our results as semi-elasticities and reduce the influence of outliers while keeping
zero observations, we apply the inverse hyperbolic sine (IHS) transformation instead of
taking natural logarithms.10
As pointed out in recent studies, the NICS data also exhibits significant drawbacks
(Lang, 2013, 2016; Levine and McKnight, 2017). Erste, it can only measure flows of
10For convenience, we refer to the IHS transformation as log throughout the paper. Wir
provide robustness checks in levels for our main specifications in the Appendix.
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weapons but does not allow inferring the stock of firearms or ownership levels. Zweite,
flows might be substantially understated as about 22% of firearm sales are between private
parties and occur in states which do not require BGCs for private transactions (Müller,
Hepburn, and Azrael, 2017). Dritte, a BGC can occur for the purchase of multiple
weapons, as well as an exchange of an old for a new firearm. Vierte, the data does
not distinguish between approved and rejected BGCs, and even an approved check does
not guarantee the sale of a firearm. Endlich, some states require a BGC for a concealed
carry permit application but not for a handgun purchase itself. Other states are running
regular or irregular re-checks on existing permit holders and thereby inflate the counts or
produce outliers.
We believe that our setup mitigates some of these problems. To start with, Die
aforementioned anecdotes, as well as findings from California by Studdert et al. (2017),
indicate that many handgun purchases during the demand shock in late 2012 were made
by new gun owners. With few sales to pre-existing gun owners, this should strengthen the
correlation between handgun sale BGCs and changes in firearm ownership. Sales outside
the NICS through private transactions and particularly gun shows are a concern but
would only invalidate our results if they were more common in NoDelay states during
the sales hike. Since many consumers were first-time buyers, we deem it more likely
they were buying from a regular FFL dealer than privately.11 Multiple purchases are
unproblematic given our interest in the extensive margin of gun ownership. A boost in
exchanges of old for new guns in Delay states could also overstate increases in firearm
11In Appendix Section B.5, we show that neither the supply of nor the demand for gun
zeigt an (the latter measured by Google Search results) witnessed a more substantial impact
of the demand shock in NoDelay over Delay states, effectively showing that displacement
to these states does not seem to be a cause for concern.
12
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ownership in those states. Since the likelihood of such exchanges should be correlated
with pre-existing levels of gun ownership, we can control for this concern in additional
robustness checks. Außerdem, work by Mueller and Frandsen (2017) has shown that
only about 1.5% of BGCs across the U.S. are actually rejected, which severely limits the
impact of this potential source of error. There is also no strong indication that the demand
shock affected the rejection probability asymmetrically across Delay and NoDelay states.
Endlich, we add BGCs for permits to our measure of handgun sales to capture cases where
buyers obtain a permit to purchase a handgun.12
A closer investigation of the NICS data revealed several outliers and reporting issues.
Wir, daher, removed Hawaii, Illinois, Kentucky, Massachusetts, Pennsylvania, Und
Utah, as well as parts of the series for Iowa, Maryland, and Wisconsin from the sample.13
We also drop Connecticut and Michigan. Connecticut was host to the Sandy Hook
shooting and thus may have potentially experienced lower gun sales after the shooting
due to social pressure or psychological effects on residents. Michigan switched treatment
status during our period of observation from requiring a permit to not requiring a permit.
Performing the steps above yields our baseline sample consisting of 43 UNS. states for
12This procedure could not be applied for Hawaii, Illinois, and Massachusetts as permit
checks in these states may also include permits for long guns. Permits were also not added
to handgun sale checks for Florida where, for no apparent reason, almost all months
Bericht 0 permit checks (and single digits for non-zero months) until April 2013, Wann
they suddenly jump to 15,000-30,000 per month for the remainder of the sample period.
Any further reference to handgun BGCs implicitly includes BGCs made for permits unless
otherwise stated.
13Outliers are mainly due to permit re-checks and law changes associated with large
mechanic jumps in BGC activity. We provide explicit reasoning for these choices in
Appendix Section A.2.
13
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investigating the effect of delay laws on handgun sales (BL1 ). While we prefer this
restricted sample for our NICS analysis, robustness checks for our main results show that
alternative (and less restrictive) sample definitions generate qualitatively similar results.
3.2 Homicide and Mortality
For our primary outcome of interest, homicides, there are two main statistical sources in
Die Vereinigten Staaten: death certificates from the National Vital Statistics System (NVSS)
and police reports from the FBI’s Uniform Crime Reporting Program (UCR). Despite
the UCR data being widely used to study crime, they are known to suffer from reporting
issues that need to be taken into account by removing areas with unreliable data from
the sample (Targonski, 2011). Coverage is therefore not universal. The NVSS data, An
die andere Hand, contains all U.S. death certificates in a given year. We obtained the
data via the Center for Disease Control and Prevention (CDC) for the entire sample
period between November 2010 und Oktober 2013. The NVSS contains ICD-10 codes
for the underlying cause of each death, as well as the victim’s demographics, county
of residence, and injury circumstances, such as location and date. The ICD-10 codes
allow distinguishing not only between homicides, suicides, and fatal accidents but also
whether these were inflicted through a handgun or not.14 In order to increase the power
of our statistical analysis, we use the detailed geographical information in the NVSS
and collapse data at the county-month level. This provides us with a balanced panel
of homicide counts for 3,047 counties which we normalize by their 2010 population in
14Our measure of handgun-related incidents also encompasses instances when an
undetermined type of firearm was used. This should not bias our estimates in any way,
and it is corroborated by the fact that the vast majority of homicides are carried out with
handguns.
14
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100,000. This second baseline sample, denoted as BL2, covers every U.S. state apart
from Connecticut and Michigan for the same reasons as stated above, and we use it in all
analyses based on non-NICS data. Figur 2 shows the counties in our NVSS sample BL2
and highlights the states excluded in the NICS sample BL1. In robustness checks, Wir
show that applying more or less stringent sample restrictions yields very similar results.
FIGURE 2 ABOUT HERE
In order to cross-validate our results and delve deeper into homicide circumstances,
we also use the Supplementary Homicide Reports (SHR) series from the aforementioned
UCR data, bearing in mind the limitations of the data. These reports are compiled from
voluntary submissions by individual law enforcement agencies to the FBI and contain
detailed information such as demographics of victim and offender, the type of weapon
used as well as murder circumstances (z.B., argument or gang-related crime). We clean
the SHR data following the procedure described in Appendix A.4 and then collapse
observations into a balanced monthly panel for 2,091 counties. Counts are normalized
using the aggregate population in 100,000 covered by the reporting agencies within a
specific county in 2010. Both UCR and NVSS crime rates are converted into logs using
the same IHS transformation as for the NICS data.
3.3 Gun Interest and Controls
To assess whether consumers in states with and without handgun purchase delays have
similar preferences, one needs to separate initial intentions to buy handguns from actual
purchases. While we use NICS data to measure the latter, we rely on internet search data
from Google Trends to proxy for people’s intention to purchase firearms. We focus on
searches for the term “gun store,” which prior research has shown to be a good predictor
15
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of firearm purchasing intentions (Scott and Varian, 2014). Since the search data comes in
relative numbers, we adopt a technique similar to that used by Durante and Zhuravskaya
(2018) to construct a state-level panel of monthly Google searches for “gun store”.15
In addition to this, we use several control variables to account for potential con-
founders as well as differences in socio-economic characteristics across counties and states.
Our core set of covariates includes the log of population, the shares of the population
living in rural areas and below the poverty line, as well as the percentages of Black and
Hispanic inhabitants. All variables were obtained from the 2010 UNS. Decennial Census at
the county level (and aggregated for state-level analyses). Zusätzlich, we collected state-
level data on the percentage of households with internet access from the 2010 amerikanisch
Community Survey, which we include in regressions using Google search data. In selecting
these control variables, we broadly followed the choices made in prior studies which
have investigated the relationship between firearm prevalence and crime (z.B., Cook and
Ludwig, 2006; Duggan, 2001). Further variables used only for robustness checks, wie zum Beispiel
measures of gun popularity, are introduced and explained where appropriate.16
4 Empirical Strategy
4.1 Difference in Differences Approach
To estimate the effect of delay laws on handgun purchases and mortality during the
demand shock, we use a DiD regression model, which overlays the cross-sectional variation
in pre-existing purchase delay laws with time-series variation from the six-month surge in
15Further details on this procedure are reported in Appendix Section A.5.
16Summary statistics of all variables can be found in Appendix Table 30. Appendix
Tisch 31 performs mean difference tests on the primary outcome and control variables.
16
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firearm demand across the United States. To account for location-specific seasonality, alle
outcome variables are seasonally differenced by subtracting their 12-month lag (denoted
as ∆12). Seasonally differencing IHS-transformed variables approximate year-to-year
growth rates. Coefficients can thus be interpreted as either changes in (nominal) Wachstum
rates or proportional changes in the outcome variable. Similar transformations of crime
counts have, zum Beispiel, been applied in Draca, Machin, and Witt (2011). Our main
specifications thus read as follows:
∆12 log(HandgunSalesst) = α + b1(Delays × P ost1t) + B 2(Delays × P ost2t)
+ δtXs + λt + φs + ǫst
∆12 log(Homicidesct)
= α + b1(Delays × P ost1t) + B 2(Delays × P ost2t)
+ δtXc + λt + φc + ǫct
(1)
(2)
We use Equation 1 to estimate the effect of the demand surge on handgun sales in
Delay over NoDelay states. Gleichung 2 is effectively the county-level analog of Equation 1
but instead uses homicide rates as outcome variables. In these equations, the specific effect
of delay laws during the demand shock captured via Delays × P ost1t can be regarded as
a shifter for new gun owners. Delays is a dummy variable for states with delay laws as
described in Section 2.1 and summarized in Table 27, d.h., Kalifornien, Florida, Hawaii,
Illinois, Iowa, Maryland, Massachusetts, Minnesota, Nebraska, New Jersey, New York,
North Carolina, Rhode Island, Wisconsin, and the District of Columbia. P ost1t is a
dummy for time periods starting with President Obama’s re-election in November 2012
and ending after April 2013 when the proposals for a renewed assault weapons ban and
universal BGCs were defeated in the U.S. Senate. Our primary coefficient of interest
is β1 and captures the average proportionate difference in HandgunSales and Homicides
between Delay and NoDelay states during the demand shock. We also include a second
17
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interaction using the time dummy P ost2t for May 2013 bis Oktober 2013 to investigate
effects beyond the initial six months. This also allows testing whether Delay states
experience comparatively fewer handgun purchases over the entire time period or if this
is compensated by more sales later on.
Apart from time fixed-effects λt, the DiD regressions also allow for location-specific
linear trends φs and φc to account for the possibility that some areas may deviate from
general trends in BGCs and homicides. Außerdem, our regression models each also
feature a set of control variables X. We avoid concerns about “bad controls” by using
interactions of pre-determined, time-invariant factors and time fixed effects. The variables
included in this way are % Hispanic, % Black, % ländlich, the log of population, Und %
Armut. ǫ denotes the residual. The standard errors used for inference are clustered by
state as the level of treatment assignment to account for serial correlation in the error
Bedingungen. Regressions are weighted by the state/county population to reduce the impact of
less densely populated areas and to obtain U.S.-wide average effects.17
A potential alternative to our approach would be to estimate a gun owner-homicide
elasticity using Delays × P ost1t as an instrument. Our preference for the somewhat
cruder reduced-form relationship stems from two factors. The first is the limitations of
the NICS data discussed above. BGCs do not allow to draw direct inference on changes
in the existing population of gun owners, making an elasticity hardly comparable to other
Studien. This concern is compounded by issues of measurement error, as not all BGCs
lead to gun purchases, and not all purchases are reflected in the BGC counts. Our second
concern is that we do not expect the effect of gun owners on homicides to be overly large
since the vast majority of gun owners are law-abiding citizens (Fabio et al., 2016). To
17Each of these estimation decisions is reassessed in sections 5.1 Und 6.2, and we provide
supplementary results in the Appendix.
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precisely estimate such a small effect, one would need a fairly large sample at the county
level for which, Jedoch, no NICS data exists. We thus estimate the raw effect of handgun
purchase frictions on sales and homicide rates during the demand shock but do not pin
down a precise elasticity given the absence of reliable panel data on firearm ownership.
4.2 Validity of Identifying Assumptions
In order for our DiD design to yield causal effects, two assumptions need to be fulfilled.
Der Erste, commonly referred to as the parallel trends assumption, requires outcomes to
have evolved similarly in the absence of treatment. This may create valid concerns as
delay laws have not been exogenously assigned to states, and as such, any differential
reaction to the shock could just be an expression of differences in unobservables. Wir
take several measures to alleviate concerns that this assumption may be violated. Erste,
we show that our outcome measures were following similar trends in Delay and NoDelay
states prior to the demand shock to prevent that our estimates are simply picking up
pre-treatment divergence. As we can see from Panels A and B in Figure 3, handgun
sales and homicides in both groups of states are sharply diverging during the six-month
window of increased firearm demand. There is also a slight divergence for handgun sales
in preceding years which highlights the need for seasonal differencing.18 Second, Wir
report results with location-specific linear time trends for all our specifications as a first
robustness check. In order to credibly identify pre-existing trends, our baseline sample
length uses an asymmetric sample period 36 months before to 12 months after the 2012
18Appendix Figures 23/24 Und 25/26 depict the evolution of both variables in levels
and 12-month growth rates.
19
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election (November 2009 bis Oktober 2013) in the spirit of Wolfers (2006).19 Endlich, Wir
also perform an event-study analysis to investigate concerns about non-linear pre-trends.
FIGURE 3 ABOUT HERE
The second prerequisite is the absence of correlated shocks, d.h., other events coinciding
with the demand hike and being positively (negatively) correlated with the existence of
delay laws but negatively (positively) with BGCs and homicide rates. As argued above,
the outcome of the 2012 election, as well as the timing of the Sandy Hook shooting, Sind
unrelated to any relevant outcome variables and were arguably the most notable events at
that time. We tackle the remaining concerns in three ways: Erste, all regressions control
for socio-demographic factors known to be correlated with both gun ownership and crime.
Zweite, we corroborate the role of delay laws by running horserace regressions where we
add interactions of time dummies with potential confounders related to political leanings
as well as preferences for and supply of firearms. Endlich, in Section 5.3, we use Google
search data to show that the divergence in gun sales after the shock does not coincide
with a similar divergence in the interest to purchase a firearm.
5 The Effect of Delay Laws on Firearm Purchases
5.1 Ergebnisse
TABLE 1 ABOUT HERE
19Note that after applying seasonal differencing, the nominal sample period starts in
November 2010 and covers 24 months before and 12 months after treatment onset.
20
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In Table 1, we estimate the differential impact of the 6-month demand hike in Delay
states on our handgun sale measure as well as total and non-handgun sale BGCs per
capita. The main coefficient of interest is β1 from Equation 1, which represents the
percentage difference of the sales rate response to the demand shock in Delay states
compared to NoDelay states. Column 1 shows a significant negative effect in the first six
months after the Presidential election and a positive non-significant effect in the second
Zeitraum. This potential postponement effect, Jedoch, disappears when adding controls
in column 2, while the coefficient for the Post1 period remains marginally significant.
After adding state-specific linear time trends in column 3 and accounting for potential
pre-trends, the estimate for β1 gains precision while β2 decreases further. A very likely
explanation for this result would be that this specification reduces noise from diverging
trends in smaller states without significantly influencing the overall (weighted) coefficient.
Our preferred estimate is the more conservative specification in column 3.20 Der
results imply that sales rates were 7.3% lower in Delay states during the first six months
than in NoDelay states.21 Columns 4 Zu 7 show that delay laws did not significantly affect
overall BGCs or other gun-related transactions like long gun sales.
5.2 Robustness Checks
As highlighted in Section 4.2, our identification strategy hinges on the validity of the
parallel trends assumption and the absence of correlated shocks. Even though our results
20Both specifications are informative, Jedoch, in our view. As we do not know whether
the ‘true’ model exhibits trends, it is ex-ante unclear whether column 2 oder 3 sollte sein
bevorzugt. Wir, daher, report specifications with and without trends for all results in
order to provide a more complete picture.
21Note that for all results in logs (IHS), the interpretation of the coefficients is a change
in percentages. In levels, the coefficients represent percentage point changes.
21
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in Table 1 are robust to the inclusion of state-specific linear trends, one may argue that
this does not accurately capture non-linear pre-trends. We investigate this possibility
using an event-study design based on column 2 in Table 1, in which we allow for quarterly
treatment effects. The results are depicted in Panel A of Figure 4 and show no indication
of non-linear pre-trends.22
In the two years before November 2012, we do not observe
a clear pattern of up- or downward trends in our estimation. In the quarter following
Die 2012 Presidential election, Jedoch, the effect of Delay states on handgun sales turns
significantly negative. After that, the coefficients gradually move back to the pre-period
level and remain insignificant for the entire Post2 period. This also provides additional
evidence against the possibility that firearm purchases were merely postponed.
FIGURE 4 ABOUT HERE
In Appendix Section B.1, we demonstrate that no other factors related to the exis-
tence of delay laws systematically affected handgun sales during the demand shock and
provide a host of additional robustness and sensitivity checks. These additional analyses
suggest that the omission of Texas reduces the effect, as the state’s regression weights
are redistributed to a large number of states.
If each state suffers from measurement
error with some probability, spreading the weights will increase the overall impact of
mismeasurement. Außerdem, population weighting is necessary to correctly capture
countrywide effects as the effect arises predominantly in urban areas. Placebo regressions,
22Für diese Analyse, we aggregate the data into 3-month bins starting in November
since “classic” quarters would result in one fully and two partially treated time periods.
Appendix Figure 31 shows the same graph using monthly data. Appendix Figure 27
reports a similar event study graph without seasonal differencing extending over a longer
Zeitraum.
22
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different sample definitions, removing single states from the sample, results in levels
and/or without seasonal differencing, weighting by the adult population, controlling
for the economic environment, and using alternative clustering techniques confirm the
robustness of our findings.
5.3 Mechanismen
Having established different reactions in handgun sales between Delay and NoDelay states,
we proceed by evaluating whether our findings could be driven by impulsive consumers.
The first appraoch to characterize impulsive agents is the potential divergence between
plans and actions.
Mit anderen Worten, impulsive consumers may decide to buy a firearm
under the influence of transient emotions but eventually do not buy since these emotions
have already passed. This should not be observed for regular, non-impulsive consumers if
they make a perfectly rational purchase decision. Jedoch, a delay in receiving the gun
makes the purchase also less attractive for non-impulsive consumers since it reduces the
item’s net present value. Wenn, Jedoch, the decision not to buy is driven predominantly by
standard exponential discounting, we should observe that longer delays reduce purchases
substantially more than shorter delays. Impulsive agents, Jedoch, would be deterred by
any delay since they cannot get hold of the firearm while being in a particular emotional
state. The second key characteristic of impulsiveness would thus be that even very short
delays should have a notable impact on the likelihood to buy.23
TABLE 2 ABOUT HERE
23These predictions can also be formally derived in a theoretical framework which is
available on request but omitted here for the sake of space.
23
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We start by investigating the congruence between plans to buy firearms and actual
sales. This analysis uses Google searches for the term “gun store,” which serves as a proxy
for public interest in buying a gun and has been identified as a strong predictor for firearm
purchasing intentions in previous research by Scott and Varian (2014). Columns 1 Und 2
in Table 2 repeat our preferred regression specifications using Google searches for “gun
store” as the dependent variable. We do not detect large or significantly different changes
in search results, which provides evidence that the different evolution of gun sales in the
wake of the demand shock was not driven by different preferences for and intentions to
buy firearms.24 This is also additional evidence that our results are unlikely to be driven
by unobserved state heterogeneity. Wichtiger, these findings indicate a mismatch
between firearm purchase intentions and actual sales in Delay states. Jedoch, diese
results could also reflect that potential buyers do not know their state’s firearm laws
while searching for a gun store but only learn about delays at a later point and then
deliberately decide not to buy. For such non-impulsive consumers, we should observe
that decreasing delay lengths smoothly reduce the effect, which we test for next.
In columns 3 Zu 10 of Table 2, we use our two main specifications from Table 1 Und
gradually exclude states with delay lengths exceeding 30, 14, Und 3 Tage. The table also
features tests for coefficient equality of β1 in the short-delay and the baseline sample.
Gesamt, we do not detect strong variations in the estimated coefficients for β1. Im
most restrictive specifications 9 Und 10, with only four treatment states and at most
three days of delay, the estimates are still very close to the baseline in columns 3 Und
4. The Wald tests can never confidently reject the null hypothesis of coefficient equality
24Figur 28 in the Appendix shows the development of Google searches between
November 2009 und Oktober 2013 graphically. A regression using levels and producing
similar results can be found in Appendix Table 28.
24
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for β1. The absence of a systematic decrease in the effect size suggests that gun buyers
may, in fact, respond more to the presence of a delay per se rather than its length.25
This evidence lends further support to the above conjecture that the difference in sales
between the two groups of states is predominantly driven by impulsive consumers.
Ein anderer, competing explanation for the relative drop in handgun sales would be fear of
tighter gun legislation. Such legislation would be particularly binding in NoDelay states
which generally exhibit weaker gun legislation. The results in this and the previous section
offer some insights into why this may not be the case. Erste, the Google search results
in Table 2 favor impulsiveness as an explanation over rational, forward-looking behavior.
Zweite, since firearm ownership is a constitutional right and handgun ownership, In
besondere, cannot easily be prohibited by the states, any belief in substantially more
binding handgun ownership restrictions may be classified as distorted.26 Holding such
distorted beliefs makes further non-rational behavior conceivable. Dritte, the robustness
checks in Table 7 and Appendix Sections B.1 and B.2 show that gun law strictness (oder
its absence) by and large does not explain away the effect of delay laws.
6 The Effect of Delay Laws on Homicides
6.1 Ergebnisse
Having found that handgun sales increased significantly less in Delay states during the
2012 firearm demand shock, we investigate whether there was also a corresponding effect
25These findings are corroborated by a triple difference analysis presented in Appendix
Tisch 35. In Appendix Table 29, we also show that including transaction costs from, z.B.,
gun licensing fees in our regressions does not qualitatively change our findings regarding
the effect of purchase delay laws.
26This follows from the landmark ruling of D.C. v Heller, 554 UNS. 570 (2008).
25
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on homicide rates. Tisch 3 shows the results from Equation 2. Observations are now
at the county-month level, and the sample includes all states previously omitted due to
measurement error in the NICS data. Column 1 shows that Delay states saw a significant
relative drop in gun homicide rates by 2.4% after the start of the firearm demand shock
and an insignificant 1.4% relative decrease during Post2. Controlling for observables in
column 2 yields a significant 2.2% relative drop in Delay states’ handgun homicide rates
during the treatment period Post1 and an insignificant relative decline of 1.8% in Post2.
The inclusion of county trends in column 3 mainly leads to a loss in precision but only
slightly diminishes β1 to −0.019, which is still significant at 5%.27
FIGURE 3 ABOUT HERE
Columns 4 Und 5 show that the P ost1 effect for handgun homicides is also reflected in
decreased aggregate homicide rates of similar magnitude. This effect is significant at the
5% level without trends but loses significance when these are included. Vor allem, there is
virtually no impact of delay laws on overall homicides in the P ost2 period. The reason for
this becomes apparent when looking at specifications 6 Und 7, which show a significant
increase during P ost2 for non-handgun homicides. A straightforward explanation could
be that the reaction of NoDelay states reflects two different channels through which
increased handgun ownership can affect homicides. One would be a lethality effect by
which random acts of aggression or anger turn into the shooting and killing of another
person. The second effect would be a substitution effect whereby homicides are simply
carried out using handguns instead of other weapons with no aggregate effect. While the
27Our results thus imply an elasticity of homicide with respect to gun sales of between
0.23 Und 0.3. This compares to an elasticity of 0.2 reported in Duggan (2001) oder 0.1-0.3
in Cook and Ludwig (2006).
26
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former suggests an immediate, impulsive killing that would not have arisen without a gun,
the latter constitutes a less specific crime that would have taken place in any case. Unser
results are indicative of both effects, with lethality being more prevalent during Post1
and substitution dominating the Post2 period (possibly because homicides are generally
more prevalent in the months of the year also included in Post2 ). Since our main interest
is delay laws’ aggregate effects, the remainder of the paper focuses on the lethality effect
and the impact of delay laws on handgun-related homicides during the Post1 period.
Columns 8 Und 9 use the violent crime rate (following the FBI’s definition) as the
dependent variable to investigate whether the decrease in homicides may have been
counteracted by an increase in other types of violent crime and thus provide a test of the
“more guns, less crime” hypothesis. The estimated coefficients, Jedoch, are insignificant,
small in magnitude for the Post1 period and point in the same direction as the coefficient
for homicides. If anything, more handguns thus increased violent crime in our setting.28
6.2 Robustness Checks
We run similar checks as in Section 5.2 to establish the validity of our identification
strategy. Erste, we investigate the possibility of non-linear pre-trends using the same
event-study design as for the NICS data. Panel B of Figure 4 indeed does not show
any systematic effect for handgun-induced homicides before the onset of the treatment.29
28Appendix Section B.3 decomposes the overall violent crime rate and shows that
aggregation does not hide substantial effects on individual categories of violent crime.
Appendix Section B.4 shows the effect on suicides and accidents.
29Appendix Figure 32 reports a similar event study graph using monthly data.
Appendix Figure 29 reports a similar event study graph without seasonal differencing
extending over a more extended period.
27
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During our treatment period Post1, Jedoch, there is a clear negative impact for the first
quarter following the demand shock and a slightly smaller one for the second treatment
quarter, which lines up with the patterns observed for handgun sales rates in Panel
A of Figure 4.30
In Appendix Section B.2, we show that our findings on handgun
homicide rates are also not a by-product of underlying differences in political leanings,
law stringency, and preferences for and supply of firearms, and we discuss and report
placebo checks, state-level results, and sensitivity to alternative sample definitions, Daten
transformation, and weighting choices. As with the BGC results, population weighting
is necessary to correctly capture countrywide effects as the effect arises predominantly in
urban areas. Placebo regressions, different sample definitions, removing individual states
from the sample, results in levels and/or without seasonal differencing, weighting by the
adult population, controlling for the economic environment, applying other clustering
Techniken, and using state-level aggregates confirm the robustness of our findings.
6.3 Mechanismen
Abschnitt 5.3 provided tentative evidence that impulsive consumers are likely to drive the
differences in handgun sale BGCs between Delay and NoDelay states. In diesem Abschnitt,
we provide evidence that our results on homicides can also be traced back to impulsive
behavior. We do so by taking a closer look at the type of additional handgun homicides
in NoDelay states (or equivalently, which were “prevented” in Delay states).
30Appendix Figure 30 shows no systematic effect on non-handgun homicides before or
during our treatment. The positive effect during Post2 in the baseline regressions applies
to all three-month periods but is only statistically significant for May to July 2013.
28
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Panel A of Table 4 presents the results split up by victim sex with a particular focus
on the 20 Zu 29 age group, into which the majority of first-time buyers should fall.31 The
results show that men make up about 2/3 of the victims while women account for 1/3.
The coefficients for female victims, Jedoch, are more precisely estimated. Both male
and female victims are predominantly aged 20 Zu 29. These findings suggest that female
victims are overrepresented, as less than 10% of overall homicide victims are women in our
data.32 Given this and our evidence on impulsive consumers, we investigate the role of
domestic violence. To do so, we split the handgun homicide victims into those who were
shot in their homes and those who were assaulted elsewhere. Panel B of Table 4 Berichte
the corresponding results. For the male victims, we find that the entire effect is driven
by attacks outside their homes. Female victims, andererseits, are predominantly
assaulted in their place of living, consistent with instances of domestic violence.
To further investigate the role of domestic violence and impulsive killings more gener-
ally, we present results using the UCR SHR data on homicide circumstances in Panel C of
Tisch 4.33 Columns 1 Zu 2 show the baseline specification for handgun homicides reported
31Appendix Table 32 shows corresponding results for all other age groups. We also
report victim splits by race in Appendix Table 33 and show that, in line with the overall
demographics of homicide victims in the United States, victims tend to be almost evenly
categorized as ’White’ and ’Black.’
32To judge how common homicides of each category are, Panels A, B, and C of Table 4,
as well as Appendix Tables 32 Und 33, include an additional row reporting the mean of
the non-differenced dependent variable in levels.
33As outlined in Section 3.2, this data exhibits a more restricted coverage. Appendix
Tisch 34 shows that the UCR SHR data yield qualitatively similar estimates compared
to the NVSS data in our Post1 period of interest. A map illustrating the exact coverage
for the UCR data is shown in Appendix Figure 12.
29
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in the UCR SHR and then split these into specific murder circumstances. The results for
aggregate handgun homicides have the same sign as those using the NVSS data but are
only about 2/3 in size and insignificant, likely due to the more limited coverage and data
Qualität. The results in columns 3 Und 4, Jedoch, indicate that deadly assaults related
to arguments account for the main part of the additional handgun homicides in NoDelay
Staaten. Unlike the aggregate handgun murder rate, this effect is also highly significant.
All other types of homicide circumstances such as brawls, (organized) crime, and defense,
as well as other/undetermined, do not seem to be systematically affected during the Post1
Zeitraum. These findings lend further support to the hypothesis that impulsive consumers
are driving the differences in handgun homicides during the demand shock.
TABLE 4 ABOUT HERE
Summarizing these findings, we observe that the additional homicides of females in
NoDelay states primarily happened inside their home, predominantly to women between
20 Und 29, and often as a result of arguments. Homicides of men, stattdessen, passiert
primarily outside their home, but also primarily because of arguments. Similar to women,
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6
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.
male victims are typically 20-29 Jahre alt. In terms of mechanisms, our findings suggest
domestic violence and other heat of the moment murders as a possible explanation
for the observed differences in homicides between Delay and NoDelay states. Diese
interpretations are in line with insights by Tangney, Baumeister, and Boone (2004) Das
F
B
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S
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T
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N
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3
impulsiveness is correlated across domains.
7 Abschluss
In light of the persistently high rate of firearm homicides in the United States, verstehen-
ing the consequences of legislation limiting access to guns is imperative. One of the main
30
0110621Review of Economics and Statistics Just Accepted MS.restby the President and Fellows of Harvard College and the Massachusetts Institute of Technology . Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) Lizenz.
arguments used by proponents of gun rights is that gun laws do not substantially affect
violent crime but impose excessive burdens on law-abiding gun owners. In this study, Wir
focus on the effects of a specific type of policy measure, handgun purchase delay laws,
and provide evidence that, while not infringing with Second Amendment rights, diese
laws can substantially reduce homicides by preventing impulsive purchases.
We present empirical evidence that states with delay laws in place saw comparatively
lower handgun sales during a demand shock after the re-election of President Obama
In 2012 and the shooting at Sandy Hook Elementary School. Further results show that
purchase delays have strong effects even when they are very short and did not affect
intentions to buy a firearm but only the likelihood of consumers making an actual handgun
purchase. In the second part of our analysis, we investigate delay laws’ effect on homicide
Tarife. Using detailed micro-data on mortality, we find a significant effect of delay laws
on handgun-related homicides during the period of the demand shock. The effect size is
um 2%, which in turn implies that about 200 homicides could have been “prevented”
during the six-month Post1 period if all U.S. states had had some sort of purchase delay
law in place. These additional homicides encompass both genders and indicate that
arguments, as well as domestic violence, constitute some of the main channels through
which handgun ownership by impulsive individuals may affect homicide rates.
We see our study as a good starting point for more nuanced investigations into the
relationship between gun ownership and crime. Erste, additional direct evidence on the
circumstances linking gun sales to violent crime is needed. While our results were able to
point in the direction of arguments and domestic violence, the results are far from clear-
cut. With increasing coverage of the FBI’s National Incident-Based Reporting System
(NIBRS ), more detailed information on particular crime incidents could be utilized to
study similar future firearm demand shocks. Zweite, given the absence of accurate data
31
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0110621Review of Economics and Statistics Just Accepted MS.restby the President and Fellows of Harvard College and the Massachusetts Institute of Technology . Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) Lizenz.
on how county-level gun ownership evolves over time, our study cannot pin down an exact
gun-homicide elasticity. The NICS data is very noisy and makes cross-state comparison
impossible at times. We thus stress the need for a more transparent, county-level version
of handgun sales than what is currently available. Endlich, we believe that more research
is needed to evaluate the costs and benefits of specific gun laws. As shown in this study,
the positive effects of purchase delays may be understated. Rigorous analyses of gun laws
may therefore help foster a more informed debate on gun policy.
Verweise
Andr´es, Antonio Rodr´ıguez and Katherine Hempstead. 2011. “Gun control and suicide:
The impact of state firearm regulations in the United States, 1995–2004.” Health Policy
101 (1):95–103.
Bernheim, Douglas B and Dmitry Taubinsky. 2018. “Behavioral public economics.” In
Handbook of Behavioral Economics, Bd. 1, edited by Douglas B Bernheim, Stefano
DellaVigna, and David Laibson. New York: Sonst, 381–516.
Card, David and Gordon B Dahl. 2011. “Family violence and football: The effect of
unexpected emotional cues on violent behavior.” Quarterly Journal of Economics
126 (1):103–143.
Chetty, Raj. 2015. “Behavioral economics and public policy: A pragmatic perspective.”
American Economic Review 105 (5):1–33.
CNBC. 2012. “The Sandy Hook effect: Gun sales rise as stocks fall.” http://www.cnbc.
com/id/100325110.
32
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Ö
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:
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/
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e
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.
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T
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e
D
u
/
R
e
S
T
/
l
A
R
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ich
C
e
–
P
D
F
/
D
Ö
ich
/
.
/
1
0
1
1
6
2
/
R
e
S
T
_
A
_
0
1
1
0
6
1
9
6
6
3
2
4
/
R
e
S
T
_
A
_
0
1
1
0
6
P
D
.
F
B
j
G
u
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S
T
T
Ö
N
0
8
S
e
P
e
M
B
e
R
2
0
2
3
0110621Review of Economics and Statistics Just Accepted MS.restby the President and Fellows of Harvard College and the Massachusetts Institute of Technology . Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) Lizenz.
CNN. 2008. “Gun sales surge after Obama’s election.” http://edition.cnn.com/2008/
CRIME/11/11/obama.gun.sales/.
CNN Money. 2012. “Obama’s re-election drives gun sales.” http://money.cnn.com/2012/
11/09/news/economy/gun-control-obama/.
Cook, Philip. 1978. The effect of gun availability on robbery and robbery murder: A
cross-section study of 50 cities. Center for the Study of Justice Policy, Institute of
Policy Sciences and Public Affairs, Duke University.
Cook, Philip J and Jens Ludwig. 2006. “The social costs of gun ownership.” Journal of
Public Economics 90 (1):379–391.
Dahl, Gordon and Stefano DellaVigna. 2009. “Does movie violence increase violent crime?”
Vierteljährliches Journal of Economics 124 (2):677–734.
Depetris-Chauvin, Emilio. 2015. “Fear of Obama: An empirical study of the demand for
guns and the US 2008 presidential election.” Journal of Public Economics 130:66–79.
Draca, Mirko, Stephen Machin, and Robert Witt. 2011.
“Panic on the streets of
London: Police, crime, and the July 2005 terror attacks.” American Economic Review
101 (5):2157–81.
Duggan, Markieren. 2001.
“More guns, more crime.”
Journal of Political Economy
109 (5):1086–1114.
Duggan, Markieren, Randi Hjalmarsson, and Brian A Jacob. 2011. “The short-term and
localized effect of gun shows: Evidence from California and Texas.” Review of
Economics and Statistics 93 (3):786–799.
33
l
D
Ö
w
N
Ö
A
D
e
D
F
R
Ö
M
H
T
T
P
:
/
/
D
ich
R
e
C
T
.
M
ich
T
.
e
D
u
/
R
e
S
T
/
l
A
R
T
ich
C
e
–
P
D
F
/
D
Ö
ich
/
.
/
1
0
1
1
6
2
/
R
e
S
T
_
A
_
0
1
1
0
6
1
9
6
6
3
2
4
/
R
e
S
T
_
A
_
0
1
1
0
6
P
D
.
F
B
j
G
u
e
S
T
T
Ö
N
0
8
S
e
P
e
M
B
e
R
2
0
2
3
0110621Review of Economics and Statistics Just Accepted MS.restby the President and Fellows of Harvard College and the Massachusetts Institute of Technology . Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) Lizenz.
Durante, Ruben and Ekaterina Zhuravskaya. 2018.
“Attack when the world is not
watching? US news and the Israeli-Palestinian conflict.” Journal of Political Economy
126 (3):1085–1133.
Edwards, Griffin Sims, Erik Nesson, Joshua J Robinson, and Fredrick E Vars. 2018.
“Looking down the barrel of a loaded gun: The effect of mandatory handgun purchase
delays on homicide and suicide.” Economic Journal 128 (616):3117–3140.
Fabio, Anthony, Jessica Duell, Kathleen Creppage, Kerry O’Donnell, and Ron Laporte.
2016. “Gaps continue in firearm surveillance: Evidence from a large US city Bureau of
Police.” Social Medicine 10 (1):13–21.
Federal Bureau of Investigation. 2016.
“2016 crime in the United States, expanded
homicide data Table 4.” https://ucr.fbi.gov/crime-in-the-u.s/2016/crime-in-the-u.
s.-2016/tables/expanded-homicide-data-table-4.xls.
Fowler, Katherine A, Linda L Dahlberg, Tadesse Haileyesus, and Joseph L Annest. 2015.
“Firearm injuries in the United States.” Preventive Medicine 79:5–14.
Heller, Sara B, Anuj K Shah, Jonathan Guryan, Jens Ludwig, Sendhil Mullainathan, Und
Harold A Pollack. 2017. “Thinking, fast and slow? Some field experiments to reduce
crime and dropout in Chicago.” Quarterly Journal of Economics 132 (1):1–54.
Huffington Post. 2013. “Gun sales exploded in the year after Newtown shooting.” http://
www.huffingtonpost.com/2013/12/06/gun-sales-newtown n 4394185.html.
International Business Times. 2012.
“Romney so ‘shellshocked’ by election
loss
Er
didn’t write
A
concession
speech.”
http://www.ibtimes.com/
romney-so-shellshocked-election-loss-he-didnt-write-concession-speech-866316.
34
l
D
Ö
w
N
Ö
A
D
e
D
F
R
Ö
M
H
T
T
P
:
/
/
D
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R
e
C
T
.
M
ich
T
.
e
D
u
/
R
e
S
T
/
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A
R
T
ich
C
e
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ich
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3
0110621Review of Economics and Statistics Just Accepted MS.restby the President and Fellows of Harvard College and the Massachusetts Institute of Technology . Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) Lizenz.
Kleck, Gary. 2004. “Measures of gun ownership levels for macro-level crime and violence
research.” Journal of Research in Crime and Delinquency 41 (1):3–36.
Kovandzic, Tomislav, Mark E Schaffer, and Gary Kleck. 2013. “Estimating the causal
effect of gun prevalence on homicide rates: A local average treatment effect approach.”
Journal of Quantitative Criminology 29 (4):477–541.
Lang, Matthew. 2013. “Firearm background checks and suicide.” Economic Journal
123 (573):1085–1099.
———. 2016.
“State firearm sales and criminal activity: Evidence from firearm
background checks.” Southern Economic Journal 83 (1):45–68.
Levine, Phillip B. and Robin McKnight. 2017. “Firearms and accidental deaths: Beweis
from the aftermath of the Sandy Hook school shooting.” Science 358 (6368):1324–1328.
Luca, Michael, Deepak Malhotra, and Christopher Poliquin. 2017. “Handgun waiting
periods reduce gun deaths.” Proceedings of the National Academy of Sciences
114 (46):12162–12165.
Ludwig, Jens and Philip J Cook. 2000. “Homicide and suicide rates associated with
implementation of the Brady Handgun Violence Prevention Act.”
Journal of the
American Medical Association 284 (5):585–591.
Müller, Matthew, Deborah Azrael, and David Hemenway. 2002. “Firearm availability and
suicide, homicide, and unintentional firearm deaths among women.” Journal of Urban
Health 79 (1):26–38.
35
l
D
Ö
w
N
Ö
A
D
e
D
F
R
Ö
M
H
T
T
P
:
/
/
D
ich
R
e
C
T
.
M
ich
T
.
e
D
u
/
R
e
S
T
/
l
A
R
T
ich
C
e
–
P
D
F
/
D
Ö
ich
/
/
.
1
0
1
1
6
2
/
R
e
S
T
_
A
_
0
1
1
0
6
1
9
6
6
3
2
4
/
R
e
S
T
_
A
_
0
1
1
0
6
P
D
.
F
B
j
G
u
e
S
T
T
Ö
N
0
8
S
e
P
e
M
B
e
R
2
0
2
3
0110621Review of Economics and Statistics Just Accepted MS.restby the President and Fellows of Harvard College and the Massachusetts Institute of Technology . Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) Lizenz.
Müller, Matthew, David Hemenway, and Deborah Azrael. 2007. “State-level homicide
victimization rates in the US in relation to survey measures of household firearm
ownership, 2001–2003.” Social Science & Medicine 64 (3):656–664.
Müller, Matthew, Lisa Hepburn, and Deborah Azrael. 2017.
“Firearm acquisition
without background checks: results of a national survey.” Annals of Internal Medicine
166 (4):233–239.
Moody, Carlisle E and Thomas B Marvell. 2005. “Guns and crime.” Southern Economic
Zeitschrift 71 (4):720–736.
Mueller, David G and Ronald Frandsen. 2017. “Trends in firearm background check
applications and denials.” Journal of Public Affairs 17 (3):e1616.
New Yorker. 2014. “The reckoning.” http://www.newyorker.com/magazine/2014/03/17/
the-reckoning.
Nunn, Nathan and Nancy Qian. 2011. “The potato’s contribution to population and
Urbanisierung: evidence from a historical experiment.” Quarterly Journal of Economics
126 (2):593–650.
Rudolf, Kara E, Elizabeth A Stuart, Jon S Vernick, and Daniel W Webster. 2015.
“Association between Connecticut’s permit-to-purchase handgun law and homicides.”
American Journal of Public Health 105 (8):e49–e54.
Scott, Steven L. and Hal R. Varian. 2014. “Bayesian variable selection for nowcasting
economic time series.” In Economic Analysis of the Digital Economy, NBER Chapters.
National Bureau of Economic Research, Inc, 119–135.
36
l
D
Ö
w
N
Ö
A
D
e
D
F
R
Ö
M
H
T
T
P
:
/
/
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R
e
C
T
.
M
ich
T
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u
/
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0110621Review of Economics and Statistics Just Accepted MS.restby the President and Fellows of Harvard College and the Massachusetts Institute of Technology . Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) Lizenz.
Siegel, Michael, Molly Pahn, Ziming Xuan, Craig S. Ross, Sandro Galea, Bindu Kalesan,
Eric Fleegler, and Kristin A. Goss. 2017. “Firearm-related laws in all 50 US states,
1991-2016.” American Journal of Public Health 107 (7):1122–1129.
Siegel, Michael, Craig S Ross, and Charles King. 2013. “The relationship between gun
ownership and firearm homicide rates in the United States, 1981–2010.” American
Journal of Public Health 103 (11):2098–2105.
Studdert, David M, Yifan Zhang, Jonathan A Rodden, Rob J Hyndman, and Garen J
Wintemute. 2017.
“Handgun acquisitions in California after two mass shootings.”
Annals of Internal Medicine 166 (10):698–706.
Tangney, June P, Roy F Baumeister, and Angie Luzio Boone. 2004. “High self-control
predicts good adjustment, less pathology, better grades, and interpersonal success.”
Journal of Personality 72 (2):271–324.
Targonski, Joseph Robert. 2011. A comparison of imputation methodologies in the
offenses-known Uniform Crime Reports. Ph.D. These, University of Illinois at Chicago.
The Intercept. 2015. “Gun industry executives say mass shootings are good for business.”
https://theintercept.com/2015/12/03/mass-shooting-wall-st/.
Vox. 2016. “What happens after a mass shooting? Americans buy more guns.” http://
www.vox.com/2016/6/15/11936494/after-mass-shooting-americans-buy-more-guns.
Wolfers, Justin. 2006. “Did unilateral divorce laws raise divorce rates? A reconciliation
and new results.” American Economic Review 96 (5):1802–1820.
37
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Total
Handgun sale
Non-handgun sale
S
k
C
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H
C
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N
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Ö
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G
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B
F
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2,000,000
1,500,000
1,000,000
500,000
0
Jan 2007
Jan 2007
Jan 2007
Jul
Jul
Jul
Jan 2008
Jan 2008
Jan 2008
Jul
Jul
Jul
Jan 2009
Jan 2009
Jan 2009
Jul
Jul
Jul
Jan 2010
Jan 2010
Jan 2010
Jul
Jul
Jul
Jan 2011
Jan 2011
Jan 2011
Jul
Jul
Jul
Jan 2012
Jan 2012
Jan 2012
Jul
Jul
Jul
Jan 2013
Jan 2013
Jan 2013
Jul
Jul
Jul
Jan 2014
Jan 2014
Jan 2014
Jul
Jul
Jul
Jan 2015
Jan 2015
Jan 2015
Jul
Jul
Jul
Figur 1: NICS BGCs
l
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.
Notes: Monthly federal NICS BGCs between November 2007 und Oktober 2015 In
absolute numbers. The sample encompasses data for all states consistently included
in our main specification as per Section 3.1. The light gray area is our sample window;
the dark grey area depicts the six months after the 2012 election and the shooting at
Sandy Hook. The gray line shows BGCs for handguns, the dashed black line all other
firearm-related BGCs, and the solid black line displays the sum of the two.
F
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0110621Review of Economics and Statistics Just Accepted MS.restby the President and Fellows of Harvard College and the Massachusetts Institute of Technology . Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) Lizenz.
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.
Delay states
NoDelay states
Not in NICS sample (BL1)
Not in NVSS sample (BL2)
Figur 2: States and counties represented in the NICS and NVSS samples
Notes: Map of the United States showing the states contained in the NICS BGC data and
counties contained in the NVSS homicide data. Dark gray counties are located in NoDelay
Staaten. Light gray counties are located in Delay states. Shaded states are dropped from
the NICS sample. Near-black counties are not included in the NVSS sample.
F
B
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G
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39
0110621Review of Economics and Statistics Just Accepted MS.restby the President and Fellows of Harvard College and the Massachusetts Institute of Technology . Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) Lizenz.
Delay states
NoDelay states
D ec 2009
D ec 2009
Feb 2010
Feb 2010
A pr 2010
A pr 2010
Jun 2010
Jun 2010
A ug 2010
A ug 2010
Oct 2010
Oct 2010
D ec 2010
D ec 2010
Feb 2011
Feb 2011
A pr 2011
A pr 2011
Jun 2011
Jun 2011
A ug 2011
A ug 2011
Oct 2011
Oct 2011
D ec 2011
D ec 2011
Feb 2012
Feb 2012
A pr 2012
A pr 2012
Jun 2012
Jun 2012
A ug 2012
A ug 2012
Oct 2012
Oct 2012
D ec 2012
D ec 2012
Feb 2013
Feb 2013
A pr 2013
A pr 2013
Jun 2013
Jun 2013
A ug 2013
A ug 2013
Oct 2013
Oct 2013
(A) Log BGC rate for handguns
Delay states
NoDelay states
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A
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D
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D ec 2009
D ec 2009
Feb 2010
Feb 2010
A pr 2010
A pr 2010
Jun 2010
Jun 2010
A ug 2010
A ug 2010
Oct 2010
Oct 2010
D ec 2010
D ec 2010
Feb 2011
Feb 2011
A pr 2011
A pr 2011
Jun 2011
Jun 2011
A ug 2011
A ug 2011
Oct 2011
Oct 2011
D ec 2011
D ec 2011
Feb 2012
Feb 2012
A pr 2012
A pr 2012
Jun 2012
Jun 2012
A ug 2012
A ug 2012
Oct 2012
Oct 2012
D ec 2012
D ec 2012
Feb 2013
Feb 2013
A pr 2013
A pr 2013
Jun 2013
Jun 2013
A ug 2013
A ug 2013
Oct 2013
Oct 2013
(B) Log homicide rate
Figur 3: Evolution of outcome variables in Delay vs NoDelay states
Notes: Log of monthly NICS handgun BGCs per 100,000 inhabitants (panel A), Log
of monthly homicides per 100,000 inhabitants (panel B) in Delay states and NoDelay
states between November 2009 und Oktober 2013. The sample encompasses data from
all counties consistently included in our main specification. The dark grey-shaded area
includes the first six months after the 2012 election, d.h., November 2012 to April 2013.
Light grey-shaded areas are marking the same period for preceding years. For better
visibility, each series has been re-scaled to 0 on the last observation before the treatment.
40
0110621Review of Economics and Statistics Just Accepted MS.restby the President and Fellows of Harvard College and the Massachusetts Institute of Technology . Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) Lizenz.
E(cid:8)(cid:8)(cid:9)(cid:10)(cid:11) (cid:12)(cid:8) (cid:13)(cid:9)(cid:14)(cid:15)(cid:16) (cid:17)(cid:11)(cid:15)(cid:11)(cid:9)
(cid:12)Ö (cid:18)(cid:19)(cid:12)(cid:20)(cid:11)(cid:21) (cid:19)(cid:15)(cid:11)(cid:9) (cid:21)(cid:15)Ö(cid:22)(cid:23)(cid:24)Ö (cid:17)(cid:15)(cid:14)(cid:9) (cid:25)(cid:23) (cid:10)(cid:21)(cid:9)(cid:10)(cid:26)(cid:17) (cid:27)(cid:9)(cid:19) (cid:7)
(cid:28)
(cid:27)(cid:12)(cid:27)
(cid:4)(cid:4)
(cid:4)(cid:4)(cid:4)
(A) NICS BGCs
#$$%&' ($ )%*+, .’+’%
(/ 12(3’4 2+’% 4+/567/ 4(89&95%. :%2 ;
<
:(:
(cid:30)(cid:30)
(cid:30)(cid:30)(cid:30)
(cid:4)(cid:5)(cid:6)
(cid:4)(cid:5)
(cid:7)
(cid:4)(cid:5)(cid:4)
-(cid:4)(cid:5)
(cid:7)
-(cid:4)(cid:5)(cid:6)
0.050
(cid:30)(cid:31)(cid:30)
!
"
0.000
(cid:29)(cid:30)(cid:31)(cid:30)
!
"
(cid:29)(cid:30)(cid:31)(cid:30)!(cid:30)
(cid:29)(cid:30)(cid:31)(cid:30) !
(b) Handgun homicide rate
Figure 4: Event study graphs
Notes: Coefficients and 95% confidence intervals for the effect of being in a Delay
state on ∆12 Log of NICS handgun BGCs per 100,000 inhabitants (panel A) or ∆12
Log handgun homicide per 100,000 inhabitants (panel B) for each three-month period
between November 2010 and October 2013. The dark grey-shaded area includes the first
six months after the 2012 election, i.e., November 2012 to April 2013. Light grey-shaded
areas are marking the same period for preceding years.
41
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0110621Review of Economics and Statistics Just Accepted MS.restby the President and Fellows of Harvard College and the Massachusetts Institute of Technology . Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) license.
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Table 1: Handgun sale BGCs
∆12 Log of BGCs per 100,000 inhabitants
Handgun Sale
Total
Other
Delay×Post1
Delay×Post2
(3)
(1)
(2)
(4)
−0.112∗∗∗ −0.081∗ −0.073∗∗ −0.036
(0.028)
(0.041)
0.048
0.057
(0.054)
(0.062)
(0.033)
0.005
(0.086)
(0.045)
0.008
(0.066)
(5)
−0.028
(0.024)
0.053
(0.062)
(6)
0.016
(0.053)
0.113
(0.097)
(7)
0.026
(0.049)
0.127
(0.095)
Year-Month FE
Controls
State Trends
Y
N
N
Y
Y
N
Y
Y
Y
Y
Y
N
Y
Y
Y
Y
Y
N
Y
Y
Y
States
Observations
R2
43
1,516
0.446
43
1,516
0.538
43
1,516
0.591
43
1,516
0.685
43
1,516
0.721
43
1,516
0.676
43
1,516
0.756
Notes: Observations are at the state-month level. The sample period is November
2010 until October 2013, i.e., an asymmetric 36-month window 2 years before and 1 year
after the 2012 election. Standard errors clustered at the state level are in parentheses:
∗p<0.1; ∗∗p<0.05; ∗∗∗p<0.01. Included control variables are log(population), % rural, %
below poverty line, % Black and % Hispanic. All variables are as of 2010 and interacted
with Month FE. Regressions are weighted by the state population.
42
0110621Review of Economics and Statistics Just Accepted MS.restby the President and Fellows of Harvard College and the Massachusetts Institute of Technology . Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) license.
Table 2: Online searches & Handgun BGCs (delay length)
∆12 Log of handgun BGCs per 100,000 inhabitants
∆12 Log std’zed
share of Google
searches for
“gun store”
Maximum
delay
length D
Delay×Post1
4
3
Delay×Post2
Year-Month FE
Controls
State Trends
States
Observations
R2
p(β1 = −0.073)
Baseline
(=12 delay
states)
D ≤ 30
Drop NY
(=11)
D ≤ 14
Drop MD,
NC, NJ (=8)
D ≤ 3
Drop CA, DC
MN, RI (=4)
(1)
0.043
(0.072)
−0.029
(0.104)
(2)
−0.045
(0.080)
−0.116
(0.138)
(3)
−0.081∗
(0.045)
0.008
(0.066)
(4)
−0.073∗∗
(0.033)
0.005
(0.086)
(5)
−0.074
(0.049)
0.012
(0.072)
(6)
−0.072∗∗
(0.035)
0.001
(0.094)
(7)
−0.105∗∗
(0.052)
−0.001
(0.080)
(8)
−0.088∗∗
(0.041)
−0.004
(0.116)
(9)
−0.071∗∗
(0.035)
−0.131∗∗
(0.058)
(10)
−0.074∗
(0.038)
−0.173
(0.119)
Y
Y
N
49
1,764
0.276
Y
Y
Y
49
1,764
0.310
Y
Y
N
43
1,516
0.538
Y
Y
Y
43
1,516
0.591
Y
Y
N
42
1,480
0.547
Y
Y
Y
42
1,480
0.599
Y
Y
N
39
1,374
0.558
Y
Y
Y
39
1,374
0.603
Y
Y
N
35
1,230
0.612
Y
Y
Y
35
1,230
0.661
0.98
0.99
0.54
0.7
0.97
0.98
Notes: Specifications as per Table 1. Google search results include % with internet access as additional controls.
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0110621Review of Economics and Statistics Just Accepted MS.restby the President and Fellows of Harvard College and the Massachusetts Institute of Technology . Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) license.
Table 3: Baseline: homicide rates
∆12 Log of ... per 100,000 inhabitants
Homicides
All violent crimes
Any
Other
Delay×Post1
Delay×Post2
(1)
−0.024∗∗∗
(0.009)
−0.014
(0.012)
Handgun
(2)
−0.022∗∗∗
(0.008)
−0.018
(0.015)
(3)
−0.019∗∗
(0.010)
−0.016
(0.018)
(4)
−0.024∗∗
(0.012)
0.003
(0.017)
(5)
−0.021
(0.015)
0.005
(0.022)
(6)
−0.001
(0.010)
0.023∗∗∗
(0.008)
(7)
−0.000
(0.013)
0.024∗∗
(0.011)
(8)
0.004
(0.019)
−0.018
(0.028)
4
4
Year-Month FE
Controls
County Trends
Y
N
N
Y
Y
N
Y
Y
Y
Y
Y
N
Y
Y
Y
Y
Y
N
Y
Y
Y
Y
Y
N
(9)
0.002
(0.023)
−0.019
(0.033)
Y
Y
Y
Counties
Observations
R2
3,047
109,692
0.002
3,047
109,692
0.008
3,047
109,692
0.019
3,047
109,692
0.006
3,047
109,692
0.016
3,047
109,692
0.005
3,047
109,692
0.014
2,091
75,276
0.007
2,091
75,276
0.034
Notes: Observations are at the county-month level. The sample period is November 2010 until October 2013, i.e., an asymmetric
36-month window 2 years before and 1 year after the 2012 election. Standard errors clustered at the state level are in parentheses:
∗p<0.1; ∗∗p<0.05; ∗∗∗p<0.01. Included control variables are log(population), % rural, % below poverty line, % Black and % Hispanic.
All variables are as of 2010 and interacted with Month FE. Regressions are weighted by the county population.
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0110621Review of Economics and Statistics Just Accepted MS.restby the President and Fellows of Harvard College and the Massachusetts Institute of Technology . Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) license.
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0110621Review of Economics and Statistics Just Accepted MS.restby the President and Fellows of Harvard College and the Massachusetts Institute of Technology . Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) license.
Panel A:
Victim sex
Victim age
Delay×Post1
Delay×Post2
Table 4: Effect on homicide rates: mechanisms
Victim age
∆12 Log of handgun homicides per 100,000 inhabitants
Any
Any
Male
Female
Any
20-29
Any
20-29
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
−0.022∗∗∗−0.019∗∗−0.013 −0.011 −0.011∗−0.008 −0.008∗∗−0.008∗ −0.006∗∗∗−0.006∗∗
(0.008) (0.010) (0.008) (0.009) (0.006) (0.006) (0.003) (0.005) (0.002) (0.002)
0.002 −0.002 −0.002
−0.018 −0.016 −0.018 −0.016
(0.015) (0.018) (0.013) (0.015) (0.007) (0.008) (0.005) (0.007) (0.002) (0.003)
0.005
0.002
0.002
County Trends
Mean DV levels
R2
N
0.287
0.008
Y
0.287
0.019
N
0.243
0.008
Y
0.243
0.020
N
0.099
0.012
Y
0.099
0.023
N
0.045
0.005
Y
0.045
0.014
N
0.012
0.007
Y
0.012
0.016
Panel B:
Victim sex
Place of assault
Any
Any
Place of Assault
Male
Female
Home
Not Home
Home
Not Home
Delay×Post1
Delay×Post2
(5)
(1)
(4)
(9)
0.004 −0.018∗−0.014 −0.007∗∗−0.008∗∗−0.001
(10)
(3)
(2)
−0.022∗∗∗−0.019∗∗ 0.006
0.000
(0.008) (0.010) (0.008) (0.008) (0.009) (0.011) (0.003) (0.004) (0.002) (0.003)
−0.018 −0.016 −0.012∗−0.014∗−0.008 −0.004
0.002
(0.015) (0.018) (0.006) (0.008) (0.011) (0.012) (0.005) (0.006) (0.002) (0.003)
0.001
0.000
0.001
(7)
(6)
(8)
County Trends
Mean DV levels
R2
N
0.287
0.008
Y
0.287
0.019
N
0.083
0.006
Y
0.083
0.017
N
0.159
0.011
Y
0.159
0.022
N
0.027
0.004
Y
0.027
0.014
N
0.018
0.006
Y
0.018
0.016
Panel C:
Circumstances
∆12 Log of handgun murders per 100,000 inhabitants
Circumstances
Any
Arguments
Brawls
Gang, Felony,
or Defense
All Other
Delay×Post1
Delay×Post2
(4)
(2)
(1)
(10)
(5)
(3)
−0.015 −0.018 −0.011∗∗∗−0.018∗∗∗0.002
0.003
(0.011) (0.013) (0.004) (0.006) (0.001) (0.001) (0.009) (0.010) (0.012) (0.010)
−0.008 −0.011 −0.009∗−0.015∗−0.000 −0.000 −0.011 −0.019
0.023
(0.017) (0.022) (0.005) (0.008) (0.001) (0.001) (0.008) (0.014) (0.012) (0.016)
(6)
(9)
0.002 −0.001 −0.010 −0.007
0.013
(7)
(8)
County Trends
Mean DV levels
R2
N
0.253
0.011
Y
0.253
0.022
N
0.049
0.009
Y
0.049
0.021
N
0.003
0.013
Y
0.003
0.024
N
0.080
0.022
Y
0.080
0.043
N
0.121
0.010
Y
0.121
0.026
Notes: Panels A and B: All regressions use 109,692 observations from 3,047 counties.
Panel C: All regressions use 75,276 observations from 2,091 counties. Specifications as
per Table 3.
46
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0110621Review of Economics and Statistics Just Accepted MS.restby the President and Fellows of Harvard College and the Massachusetts Institute of Technology . Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) license.