Myth:

Opponents of concealed-carry laws, such as Mayor Michael Bloomberg of New York, insist that the presence of armed citizens at mass shootings would result in even more deaths because of crossfire. But armed civilians prevented mass shootings on many occasions – in schools, a mall, and other public places – and there is no instance on record of a permit holder’s accidentally shooting a bystander – John Lott

None of the criminologists or economists who have studied concealed-carry handgun laws has found an increase in murder, suicide, or accidental death. Indeed, the vast majority of studies have found the opposite. – John Lott

An armed society is a polite society. Manners are good when one may have to back up his acts with his life. – Robert Heinlein

We see it on the news every day, yet another instance of some heroic armed citizen forcing criminals to flee from a robbery, a woman in a dark alleyway able to protect her virtue against a man twice her size, a husband protecting his wife and children from armed intruders.

Over the past several decades, the number of guns Americans own has skyrocketed. Simultaneously, gun violence has receded to levels not seen since the 1960s.

This contention rests on the idea that guns are the best means of defense and are a deterrent against criminals.

This idea is based heavily on research done by John Lott, whose research indicated that concealed carry laws reduced violence and overall crime, and that states with higher levels of gun ownership are less violent.

Linked to the idea that an armed society is a polite society.

Reality:

(12/1/14: For a more detailed examination of the More Guns, Less Crime hypothesis and John Lott, please see our recent article: http://www.armedwithreason.com/shooting-down-the-gun-lobbys-favorite-academic-a-lott-of-lies/)

(2/6/15: For a more detailed examination of Defensive Gun Use, please see our recent article: http://www.armedwithreason.com/debunking-the-defensive-gun-use-myth/)

One of the most common assertions in defense of firearm use is the argument that guns are used millions of times a year in self-defense and are therefore effective crime deterrents. There are two theoretical mechanisms that could explain this effect: 1) an attempted crime may be stopped due to the presence of a firearm; 2) a potential crime may be deterred due to a criminal’s caution in pursuing areas with high firearm ownership rates. As it turns out, neither of these explanations bear out in the data.

Why Guns Per Person is the Wrong Way to Think About Gun Control:

Before debunking both of the mechanisms outlined above, first let’s be clear about the proper metric in discussing the relationship between guns and crime.

As the graph above shows, the number of guns in the US has increased dramatically over the past few decades. This increase in the number of guns has corresponded to a decrease in violent crime. Therefore, gun advocates conclude that more guns = less crime.

However, this thought process is merely an extension of deterrence theory. We illustrated that the MAD Theory of Guns is incoherent when applied to mass shootings, and it is just as illogical when applied to violent crime.

First, let’s examine the apparent contradiction between two ostensibly incongruent facts: the number of guns in the United States has been increasing, while the gun ownership rate is decreasing. This is easily explained by the fact that many if not most gun owners buy more than one gun. Not only do hunters need several types of hunting rifles to match their prey, but also a large segment of the gun-rights advocate population has been stockpiling arsenals for a while now in preparation for social unrest or government despotism (I find neither of these arguments particularly convincing myself, though I might be persuaded about the necessity of preparing for the Zombie Apocalypse).

A person owning one gun is just as dangerous and likely to commit a homicide as a person with a dozen guns, ignoring that owning multiple guns might be a proxy for other sorts of behavioral characteristics that might be related to criminality. What we see in the data is that the United States has reached a saturation point with guns. Most people who are going to buy a gun for whatever reason have already bought one, and buying a second does not increase the gun ownership rate.

Think of it this way, 100 people with one gun each is much scarier statistically speaking than 1 person with 100 guns.This is why the gun ownership rate is the statistic to worry about much more than the overall number of guns. And to further demonstrate that it is highly unlikely that the increase in the number of guns caused the decrease in the homicide rate, consider this: If the deterrence theory is correct (which I will demonstrate is not the case), a person with one gun is just as likely to stop a crime as a person with 100 guns. The extra 99 guns don’t help.

It is merely the fact that a person owns a gun, not how many, that matters with regard to the crime debate. As gun ownership has not increased in tandem with the number of guns, it is not possible for the increase in guns to have contributed to the decrease in violent crime. The only effects that can stem from this surge in guns are deleterious. With hundreds of thousands of guns stolen every year, the stockpiling of weapons only increases the likelihood that they end up in the wrong hands.

To be clear, then: though the “number of guns” has been increasing, this is not a useful metric in empirical analysis when talking about crime. It is the per capita ownership rate (or household ownership rate), not the total number of guns that matters most.

The NRA hasn’t updated its sources since 1995:

It’s important to highlight that the only academic source which substantiates the claim that guns are used millions of times a year in self-defense is a 1995 publication by Gary Kleck and Marc Gertz from Northwestern. This paper forms the entire basis behind the National Rifle Association’s talking point that “Americans use guns for self-protection as often as 2.1 to 2.5 million times a year.” Even if this paper had statistical merit, it’s rather curious that the NRA, Congress, and the media are still using a statistic computed from data that starts in 1981, the peak of the post-Vietnam crime wave, and is clearly inconsistent with a modern reading of literature on the subject .

However, even if you felt that a paper from 1995 still has social relevance, you should know that the entire paper has since been eviscerated by scholars who have pointed out that Kleck and Gertz’ paper suffers from errors so severe that their entire estimate is useless.

For example, according to Kleck and Gertz’s paper, guns were used in self-defense in 845,000 burglaries. However, from reliable victimization surveys, we know that there were fewer than 1.3 million burglaries where someone was in the home at the time of the crime. From surveys on firearm ownership, we know that 42% of US households own firearms (at the time of the survey), 33% of which contained occupants who weren’t sleeping at the time of the burglary. In order for the burglary statistic cited in Kleck and Gertz’s paper to be true, burglary victims would have to use their firearm in self-defense more than 100% of the time. Or, burglars could only rob houses of gun owners, and those gun owners would have to use their weapons in self-defense every single time they are awake.

Another absurd conclusion made in order to get to the ‘2.5 million’ claim, is that victims of rape and robbery are more likely to use a gun in self-defense than the offender is to use a gun against the victim. This clearly is impossible as most citizens don’t carry guns with them, and criminals choose the time and place of an attack.

David Hemenway, an economist and director of the Harvard Injury Control Research Center, concludes that “one small reason to expect even a tiny percentage of responders to over report (the number of times they used a firearm in self-defense) may be enough to lead to a substantial overestimate.” Indeed, not one scholar since has been able to externally validate any of the claims made by Kleck and Gertz.

Guns are rarely used in self defense:

Now that I’ve given ample reason to be skeptical of the basis upon which the self-defense position is founded, let’s look at actual data on firearms used in self-defense.

To challenge the first way a firearm may potentially decrease crime, that is, attempted crimes may fail to materialize due to the presence of a firearm, we will use the most recent evidence from four national data sets, as provided by the Violence Policy Center.

In 2010, according to the most recent data on justifiable homicides from the FBI’s Uniform Crime Reporting (UCR) program, there were 230 justifiable homicides involving a private citizen using a firearm in self-defense during either an attempted or a completed crime. In the same year, there were 8,275 firearm homicides. This means that, for every one justifiable firearm homicide, there were 36 criminal homicides. Contrary to the gun lobby’s claim that, between 2007 and 2011, guns were used 12.5 million times in self-defense, the most reliable data on this question clearly show that firearms were used only 338,700 times in self-defense, and this includes off-duty police. Clearly, then, despite living in a country with 300 million guns, the use of firearms in self-defense appears to be an exceedingly rare phenomenon.

Two other areas of crime—violent crime and property crime—are analyzed by the Violence Policy Center, and cast serious doubt on the argument that guns are used regularly in self-defense. Between 2007 and 2011, only 0.8 percent of violent crimes involved the intended victim using a firearm in self-defense. During the same five year period, only 0.1 percent of attempted or completed property crimes involved the intended victim using a firearm in self-defense. Given that between 40-45% of American households own a gun, and less than 0.1 percent of victims of property crime end up using a gun to stop a crime, it’s impossible to suggest that guns are being effectively used in self-defense. Rather than guns serving as a useful deterrent, they instead helped to directly facilitate crime: 232,400 guns were stolen each year from U.S. households between 2005 and 2010.

You might be thinking, as many of our readers did, that 338,700 defense gun uses in a five year period (DGU) is not ‘rare’, and that, according to our own data, guns are used in self-defense 7 times as much as they are used in criminal homicides. As Devin and I have made clear in the comments section, however, this comparison is disingenuous:

The 338,700 DGUs is primarily composed of self-defense uses in which the victim would not have died in the absence of a gun. We know this to be true because the majority of firearm violence in which the victim is unarmed does not result in the death of the victim. It should be clear, then, that comparing defensive gun uses to offensive gun deaths, commits a category mistake because you are comparing variables of different magnitude. Either uses should be compared to uses, or deaths should be compared to deaths.

Thus, two potential comparisons are more appropriate:

Justifiable homicides vs criminal homicides – (deaths vs. deaths) the reason this is more accurate is that both result in a guaranteed death, and justifiable homicides function as a serviceable substitute for situations in which the death of the victim is more likely in the absence of a gun. In this case we have 230 justifiable homicides in 2010 vs 8,275 criminal homicides in 2010, which clearly weighs in favor of gun control advocates. Defensive gun use vs crimes committed with a firearm – (uses vs uses). Again, guns were used in self-defense 338,700 times between 2007-2011. In that same five year period, there were 2,277,000 crimes committed with a firearm. Let’s be clear about this: every time a gun was used in self-defense, a criminal committed fatal or non-fatal firearm violence ~7 times.Either way you look at it, offensive gun use far outweighs defensive gun uses, and there is very little evidence validate the claim that guns reliably de-escalate a criminal encounter once it happens.

The Right to Carry Battle:

The clearest test of the MAD Theory of Guns is whether Right to Carry Laws (RTC) deter crime. RTC laws are the ultimate expression of MAD Theory. Those who do choose to carry are the quintessential “good guys with guns.” To get a permit, one has to go through a background check and take several hours of coursework. Even better, concealed carry means the bad guys have no idea who is armed and who isn’t. There could be a “good guy with a gun” around any corner, ready at a moment’s notice to bring a criminal to justice. Criminals realize that any illegal act could easily be their last, and so the presence of concealed carrying citizens should imbue criminals with caution, leading to a decrease in the crime rate. If we cannot find supporting evidence of MAD Theory here, then it is safe to assert that the theory is intellectually bankrupt.

At first glance, the research appears promising for gun advocates. In his widely cited work “More Guns, Less Crime,” John Lott lays out the case for RTC laws using a comprehensive data set and the veneer of sophisticated statistical analysis. His analysis shows that RTC laws are very effective at lowering violent crime rates. At the surface level, MAD Theory seems to work.

However, even a brief glance at Lott’s findings reveals a multitude of peculiar findings that bear no resemblance to reality. As Albert Alschuler explains in “Two Guns, Four Guns, Six Guns, More Guns: Does Arming the Public Reduce Crime,” Lott’s work is filled with bizarre results.

According to Lott’s data, rural areas are more dangerous than cities. FBI data clearly shows this is not the case. In his data, the number of African-American females over the age of 65 is more highly correlated with the murder rate than the number of African-American teenagers. The number of killings committed by a stranger increases while the number of intra-family killings decreases after the passage of RTC laws. Lott also finds that there is only a weak deterrent effect on robberies, the most common street crime.

One critique of Lott’s work found that, according to Lott’s own data, RTC laws result in a positive statistically significant effect on crime in some states, and a negative statistically significant effect in others. The jumbled, contradictory, and quirky nature of these findings renders Lott’s analysis incoherent at best. Something is very wrong with his methods. To accept the statistical conclusion blindly, even in the face of obvious empirical realities, is not a good practice if we wish to create thoughtful policies on gun reform.

The suspicious nature of Lott’s findings are confirmed by other academic research. In response to John Lott’s book, “More Guns, Less Crime” a sixteen-member panel of the United States National Research Council convened to analyze the findings and statistical methods of Lott’s book. They found that the existing evidence did not support the more guns, less crime hypothesis. In 2010, a reexamination of the panel’s work concluded the following: “the most consistent, albeit not uniform, finding to emerge from the array of models is that aggravated assault rises when RTC (Right to Carry) laws are adopted. For every other crime category, there is little or no indication of any consistent RTC impact on crime.”

The most recent available meta-analysis on firearm availability and homicide, surveying over fifty international and domestic studies, finds the consistency of evidence in favor of gun regulation overwhelming:

The available evidence is quite consistent. The few case control studies suggest that households with firearms are at higher risk for homicide, particularly firearm homicide. International cross-sectional studies of high-income countries find that in countries with more firearms, both men and women are at higher risk for homicide, particularly firearm homicide. This result is primarily due to the United States, which has the highest levels of household ownership of private firearms, the weakest gun control laws, and the highest homicide rates. Time series studies of particular cities and states, and for the United States as a whole, suggest a positive gun prevalence-homicide association. Finally, perhaps the strongest evidence comes from cross-sectional analyses of U.S. regions and states. Again, places with higher levels of gun ownership are places with higher homicide rates.

In a gigantic, 120-page paper in Stanford Law Review entitled, “Shooting Down the ‘More Guns, Less Crime Hypothesis”, the authors find that the model used in Lott’s paper was riddled with inaccurate assumptions. Most problematically, Lott’s model estimates an aggregated effect for all states adopting shall-issue laws. This is faulty for at least two reasons: 1) it presupposes that shall-issue laws have a uniform effect across all states, when the effect is certainly variable; 2) the aggregated effect gives unfair weighting to states which are early adopters of shall-issue laws, and almost no weight to late adopters. We know from reliable victimization surveys that late adopters tended to experience crime increases, and so any aggregated effect will be biased to show that crime decreased after shall-issue laws were implemented.

The paper finds that, after controlling for the selection effects of very late and very early adopters, and introducing state level trends into a disaggregated model, the conclusions “largely eviscerate the more guns, less crime hypothesis.”

In short, the entire intellectual framework supporting RTC laws, and more generally The MAD Theory of Guns, has been utterly discredited That being said, although it is empirically irrefutable that more guns does not equal less crime, does the opposite hold? Do less guns mean less crime, or is there simply no significant relationship between the two?

More Guns, More Crime:

The effect of gun ownership on crime is theoretically ambiguous—it could be the case that gun ownership increases the cost of crime and thus deters potential criminals, or it could also be the case that high gun ownership rates makes it easier for criminals to obtain guns, and thus causes more lethal crimes to occur. Extricating the exact relationship between firearms and crime has proven difficult, because of the need for a reliable proxy for gun ownership that is not correlated with the crime rate.

One of the most frequently cited papers challenging the “more guns, less crime” hypothesis is a seminal paper by University of Chicago Professor Mark Duggan in which he shows that gun ownership increases the crime rate.

In this paper, Duggan found that, between 1993 and 1998 gun homicides dropped 36 percent, while non-gun homicides dropped only 18 percent. He found that one-third of the decline in gun-related homicides since 1993 can be explained by a decline in the gun ownership rate. Duggan used a clever proxy in order to estimate the rate of gun ownership, the state and country-level sales rate for the Guns & Ammo magazine.

He found that gun magazine subscription data was strongly related to the demographic characteristics that were associated with gun possession, but not correlated to the crime rate. Using this instrument, Duggan was able to show that guns cause an increase in crime, refuting the ‘reverse causality’ hypothesis in which individuals in high crime areas may hypothetically respond to the perceived threat of criminal activity through buying more firearms. Duggan therefore concludes that “increases in gun ownership lead to substantial increases in the overall homicide rate. This is driven entirely by the relationship between firearms and homicide in which a gun is used, implying that the results are not driven by reverse causation nor by omitted variables.”

To conclude:

Statistically speaking, guns are rarely used in self-defense, and thus cannot be defended on the grounds that they can reliably defuse crimes while they are happening.

The NRA bases its claim that guns are used millions of times a year in self-defense on a discredited study from 1995 that has not been validated in a single academic paper.

Concealed Carry Laws are not associated with decreases in crime, and sophisticated analyses show that, in some cases, there is an increase in aggravated assaults associated with concealed carry laws.

The best studies to date, using proxies to estimate gun availability, show that more guns lead to more crime.

*correction: Previously the article mentioned that the NRC panel met twice. They only met in 2004, and it was a separate study reexamining the NRC’s findings that was issued in 2010.