Guns and Crime

American Economic Review, 1998

So far 33 states have adopted right-to-carry concealed handgun laws. The advocates argue these laws have a deterrent effect on crime, while the opponents believe they facilitate crime by increasing gun availability. Although both sides assume that these laws affect behavior, no attempt has yet been made to model such effects using crime theory. Consequently, the empirical evidence on such effects lack a theoretical basis; for example, a highly publicized study by Lott and Mustard (1997) inappropriately models the effect of the law through a dummy variable (a binary-valued regressor). We extend the economic model of crime to formulate a theoretical basis for empirical examination of the issue. We show that using a dummy variable leads to misspecification, and use an alternative procedure to estimate the effect of concealed handgun laws in 1992 for states which had not yet adopted such laws. Our results show that the expected effect of the law on crime varies across the counties and states and depends on county-specific characteristics in a meaningful way. Such effects appear to be much smaller and more mixed than Lott and Mustard suggest, and are not crime-reducing in most cases.

Journal of Economic Behavior & Organization, 2017

Using a detailed jurisdiction-quarter level dataset, I create a proxy for illegal firearm flows: the number of firearms reported stolen in each police jurisdiction, and map their effect on crime in the U.S. Estimates show a strong, positive impact of increased stolen firearms, in the previous quarters, on firearm aggravated assaults, homicides, and robberies in the current quarter. However, no statistically significant relationship is estimated between firearm flows and non-firearm offenses, providing a crucial falsification test. Various other robustness checks, including an analysis of potential spillovers in illegal firearm flows, find no evidence of a spurious relationship driving the results.

International Review of Law and Economics, 2003

So far 33 states have adopted right-to-carry concealed handgun laws. The advocates argue these laws have a deterrent effect on crime, while the opponents believe they facilitate crime by increasing gun availability. Although both sides assume that these laws affect behavior, no attempt has yet been made to model such effects using crime theory. Consequently, the empirical evidence on such effects lack a theoretical basis; for example, a highly publicized study by Lott and Mustard (1997) inappropriately models the effect of the law through a dummy variable (a binary-valued regressor). We extend the economic model of crime to formulate a theoretical basis for empirical examination of the issue. We show that using a dummy variable leads to misspecification, and use an alternative procedure to estimate the effect of concealed handgun laws in 1992 for states which had not yet adopted such laws. Our results show that the expected effect of the law on crime varies across the counties and states and depends on county-specific characteristics in a meaningful way. Such effects appear to be much smaller and more mixed than Lott and Mustard suggest, and are not crime-reducing in most cases.

This paper analyzes the effects of the availability of firearms on gun-related homicide; moreover, it also analyzes the roles that other factors play when it comes to gun-related homicide.

The Journal of Legal Studies, 1997

Using cross-sectional time-series data for U.S. counties from 1977 to 1992, we find that allowing citizens to carry concealed weapons deters violent crimes, without increasing accidental deaths. If those states without right-to-carry concealed gun provisions had adopted them in 1992, county-and state-level data indicate that approximately 1,500 murders would have been avoided yearly. Similarly, we predict that rapes would have declined by over 4,000, robbery by over 11,000, and aggravated assaults by over 60,000. We also find criminals substituting into property crimes involving stealth, where the probability of contact between the criminal and the victim is minimal. Further, higher arrest and conviction rates consistently reduce crime.

Homicide Studies, 2005

What happens when states ease access to permits to carry concealed handguns in public places? Supporters maintain the laws can reduce violent crime rates by raising the expected costs of crime, because of criminals anticipating greater risks of injury and lower rates of success completing their crimes. Opponents argue that the laws are likely to increase violent crime, especially homicide, as heated disputes involving permit holders are more likely to turn deadly because of the greater lethality of firearms. This study uses panel data for all U.S. cities with a 1990 population of at least 100,000 for 1980 to 2000 to examine the impact of “shall-issue” concealed handgun laws on violent crime rates. The authors measure the effects of the laws using a time-trend variable for the number of years after the law has been in effect, as opposed to the dummy variable approach used in prior research. They also address many of the methodological problems encountered in previous studies. The res...

Journal of Economic Behavior & Organization, 2013

I focus on the effect of changes in public security (policing) on private security measures that potential victims can take. In particular, I look at the tradeoff between different types of private security measures-such as using or carrying guns, carrying less cash or keeping less valuables at home, and using burglar alarms or Lojack-and study how this tradeoff is affected by changes in public security. If private householders' direct security expenses are strongly substitutable with public policing (e.g., for guns which may be more useful in badly policed areas), an increase in policing results in a drop in these expenses; it also results in carrying or keeping less cash (an indirect security measure which reduces the prize a criminal can seize). If, however, householders' direct security expenses are "complementary" to policing in the sense that they are more effective when police response is rapid (e.g., for burglar alarms), more policing increases these expenses unless the efficacy of joint (public and private) security expenses on combating crime encounters very sharply diminishing returns; moreover, a rise in policing also induces carrying or keeping more cash. An increase in penalties increases the tendency to keep cash on hand, and also reduces crime, provided that as private precautions increase, with policing constant, it takes a larger increment in security spending to compensate for a specific drop in penalties. The results are consistent with some empirical trends in crime rates, policing, penalties and private precautions.

2020

We report two results. First, we evaluate the impact of a nationwide anti-firearm legislation enacted in December 2003 (Estatuto do Desarmamento, henceforth ED). Our identification strategy hinges on the hypothesis that the law had a stronger impact in places where gun prevalence was higher in the baseline. We find evidence that homicides (reduced form) and firearms prevalence (mechanism or first-stage) dropped faster in places with higher gun prevalence after the 2003. Using our preferred estimates, the ED saved between 2,000 and 2,750 lives from 2004 through 2007 in cities with more than 50,000 inhabitants in the state of São Paulo. Second, assuming the ED causes homicide only through its impact on firearms prevalence, we recover a causal estimate of the impact of firearms on homicides. One standard deviation in the prevalence of firearms reduces homicides by quarter of a standard deviation. We find no impact of both ED and firearms on property crime in general or on robberies.

2009

In their reply to our comment on their initial paper, Moody and Marvell continue their analysis of right-to-carry (RTC) laws using panel data for the period 1977-2000. But with six additional years of data now available for analysis, we think the need for further parsing of older data is of limited value in assessing the more guns, less crime hypothesis. In this comment, we add six years of data to what Moody and Marvell previously analyzed. We show that, whether one looks at the original Lott and Mustard specification, the latest Moody and Marvell specification, or a plausible alternative specification, there is consistent evidence for the unsurprising proposition that RTC laws increase aggravated assault. We address some anomalies in these models and their resulting estimates. The Lott and Mustard model, for example, suffers from omitted-variable bias in failing to control for the impact of incarceration. In addition, the Moody and Marvell model generates odd predictions of the im...

2021

This paper investigates the impact of gun control legislation on the homicide rate across two countries-the US and Canada. The Brady Act from the US creates the national background check system we use today, while the Firearms Act from Canada starts a new national background check system along with labeling certain guns as "restricted" or "banned" for civilian purchase 12. For each of these policies, I created a regression that predicts the state's or province's homicide rate based on the policy, year, alcohol consumption, police per capita, and many demographic variables to measure the policy's short-term and long-term impact on the firearm homicide rate. Based on these regressions, both acts significantly decreased firearm homicides in the long-term, but the Brady Act had a bigger impact in relation to the current firearm homicide rate at the time. Therefore, the Brady Act was more effective than the Firearms Act. One main future direction with this research is to analyze homicides caused by other means during the same timeframe. Additionally, since firearm homicides significantly decreased with these acts, it would be valuable to know if firearm suicides also decreased. II.