Data Wonk

Do More Guns Lower Crime?

That’s the theory behind proposed bill to permit guns in college buildings. Is the theory true?

By - Oct 28th, 2015 01:20 pm
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Two intellectual models dominate the discussion of guns and crime. One says more guns leads to more violent crime. If guns are easily available, petty disputes can escalate into injury or death. To reduce violence in America, you need reduce the number and availability of guns.

The other view is that having more guns in the hands of law-abiding citizens reduces crime. If criminals are confident their likely victims are unarmed they will be more likely to commit their planned crimes, in this view. Pointing to the wake of recent mass shootings, these advocates also lament there weren’t people armed and ready to shoot back. This theory is also behind the current legislative bill to permit concealed carry in college buildings.

Which side is right? An immediate problem is a shortage of accurate data, particularly research that digs below the surface. Even the basic statistics are often unreliable; the FBI crime data in particular is very dependent on the conscientiousness of local police departments, which can vary widely.

Another problem is common to most public policy research. It’s often very difficult to separate the effect of various gun laws from the many other things that may affect gun violence.

However, the dearth of solid gun violence research is to some degree deliberate and political. As a recent article in the Washington Post described, the Centers for Disease Control has not sponsored research on guns since 1997, when Congress, under pressure from the National Rifle Association, threatened to cut off CDC’s funding. Two years ago President Barack Obama ordered the CDC to resume funding firearm studies, but it has not done so, citing a lack of overall funding.

The Wisconsin concealed weapon law was also written to discourage research: “Neither a law enforcement agency nor any of its employees may sort or access information regarding vehicle stops, investigations, civil or criminal offenses, or other activities involving the agency based on the status as licensees or holders of certification cards of any individuals involved.” While the language is opaque, it seems aimed at discouraging any effort to quantify the extent to which permit holders may be involved in crime.

To a large extent, the more-guns less-crime position depends on a study by John Lott and David Mustard that compared the changes in crime in states and counties that passed laws between 1977 and 1992 that allowed citizens to carry concealed weapons, including Maine, West Virginia, Idaho, and Montana, with states that did not, such as New York, California, Illinois, and New Jersey. They concluded that violent crimes went down in states that legalized concealed carry.

Other scholars have looked at Lott’s data and disagreed with his conclusion. The criticisms (see here and here for examples) make several points. One is that Lott ignores other possible explanations for the differences, notably that during this period the crack epidemic hit the states he used as controls much harder than the states changing the concealed-weapon laws. A second is that crime randomly rises and falls over time; so that a fall in crime after a concealed carry law is passed might have happened anyway. A third concern is that the conclusions made are very sensitive to slight changes in time period, which states are included, the model chosen, and coding errors.

Since the appearance of his first paper, Lott has become the most prominent advocate for the argument that more guns drive down crime. This was evident in a commentary of his titled Americans now know: More guns = less crime published in the Journal Sentinel earlier this year. His Crime Prevention Research Center makes this very clear including links to Lott’s books with titles like More Guns, Less Crime and The Bias Against Guns.

An example of Lott’s approach is his treatment of the international comparison of guns and crimes. The next graph, taken from his web site, is meant to demonstrate that as firearms per person go up the homicides go down. He gets to this conclusion, however, by including countries whose economies, laws, and effective government often leave much to be desired.

Gun Ownership and Homicide Rates for Countires cover by the Small Arms Survey

Gun Ownership and Homicide Rates for Countires cover by the Small Arms Survey

Here is what the correlation looks like if the comparison is limited to countries at more or less the same level of development as the United States: Western Europe, the United States, Canada, New Zealand, and Australia. Now homicides go up along with the number of guns. The United States is an outlier, both in terms of gun availability and violence. Without it, the correlation between guns and deaths becomes very weak (for those technically inclined the coefficient of determination drops from .49 to .04).

Death rate vs Gun laws

Death rate vs Gun laws

 

Switzerland and Israel are often pointed to as examples of countries with a large number of guns but few gun deaths. An article in the Washington Post argues that “Israel and Switzerland are not gun-toting utopias.”

Within the United States comparisons of states pretty conclusively show that a high suicide rate is associated with weak gun laws, but are much more ambiguous when it comes to homicides. The Law Center to Prevent Gun Violence and the Brady Campaign to Prevent Gun Violence, two advocates of controls on guns issued a State Scorecard rating state gun laws in great detail. When the ratings are plotted against gun deaths the result shows states with stronger laws regulating guns have less gun deaths per capita. (Wisconsin is shown with a red dot.)

Death rate vs Gun laws

Death rate vs Gun laws

This conclusion is almost entirely due, however, to the strong relationship between gun laws and the suicide rate. (For other studies that found correlations between gun deaths and state laws see here and here. Note that the first also found a correlation between state laws and homicide rates.)

As the next plot shows, there’s also a very strong relationship between the strength of the gun laws and the responses people made to a survey as to whether they had a gun in their home. Of course the direction of causality can go either way. With tougher laws fewer people may keep guns around. Alternatively, low gun ownership may make it easier to pass gun laws.

Home storage vs laws

Home storage vs laws

An article published in the Journal of Public Health estimated that firearms were used in more than 12,000 homicides in the United States in 2005, and that 84 percent of these occurred in large- or medium-sized metropolitan areas. It also stated that firearm homicide rates are highest among young men in large urban centers and have been rapidly increasing in this population despite a general decline in violent crime in most cities.

This very concentration in urban areas suggests one reason for the lack of a significant relationship between gun control laws and homicides. As the next plot shows the states with the strongest laws are also the most urban.

Laws vs % urban

Laws vs % urban

However, even if the problem of firearm homicides is predominantly an urban issue, grouping all urban areas together misses the important differences between urban neighborhoods. Consider two police districts in Milwaukee. District 1 includes most of Downtown and the East Side. It covers the UW-Milwaukee campus. District 5 is immediately to the west and north of District 1.

Over the past four years, District 1 has seen three homicides. This translates into a rate of 1.6 per 100,000 residents, about like Canada’s. District 5’s 402 homicides translate into 46.4 per 100,000 residents, like Guatemala.

Murder Rate

Murder Rate

 

Rather than promoting more guns in District 1, perhaps a better use of the state’s resources would be to find ways to reduce the number of guns in District 5. This points out the need for more research. For example, how many people in each district have concealed carry permits? Is there a difference in the number of people agreeing that guns make them safer?

The next chart compares the annual rate of thefts. This is one area in which District 1 fares poorly compared to District 5 and Milwaukee as a  whole. Several factors could contribute to this difference, including that there are more things to steal in District 1 and perhaps a greater willingness to report thefts there.

Theft Rate

Theft Rate

The model underlying the proposed law requiring universities to allow guns in their buildings is summed up by a cartoon recently published in the Milwaukee Journal Sentinel. In it a man and a boy are studying a Gun Free Zone. The man explains that, “It means this building is a soft target where law-abiding people can’t protect themselves from the violent intentions of others.”

The cartoon suggests that “violent intentions” lend themselves to rational planning. Yet FBI statistics suggest that most murders stem from an argument that got out of control and most victims knew their muderers. Of the homicides in which the police could identify the perpetrator, a fourth of the victims were family members and about half had some other relationship.

Murder victim relationships

Murder victim relationships

This would suggest that most murderers don’t think strategically. Perhaps thieves do. Rather than promoting the arming of people living, working, and attending college in Milwaukee’s 1st Police District, a more constructive approach might be to figure out how to reduce the arms war in the 5th District.

Categories: Crime, Data Wonk, Politics

25 thoughts on “Data Wonk: Do More Guns Lower Crime?”

  1. blurondo says:

    …” the Centers for Disease Control has not sponsored research on guns since 1997, when Congress, under pressure from the National Rifle Association, threatened to cut off CDC’s funding.”

    Guns, like cigarettes, need to be treated as a matter of public health; highly regulated, highly taxed, and if you own one, your health insurance is more expensive. And that’s just the beginning.

  2. Kevin Baas says:

    This poor 2-year old’s death could have been prevented if more 2-year olds had access to guns. Just sayin’. http://www.nbcnews.com/news/us-news/georgia-boy-2-dies-after-shooting-himself-gun-police-n452826

  3. Kevin Baas says:

    I was about to cite this survey that clearly shows even republicans strongly support stricter gun control laws, such as mandatory background checks, then I noticed that they are simultaneously strongly against stricter gun control laws. http://www.pollingreport.com/guns.htm It appears somehow republican opinion on gun control has managed to achieve a quantum superposition state that can’t be explained by classical physics.

  4. Tom Bosworth says:

    The US and state constitutions authorize some laws, fail to authorize others, and explicitly prohibit still others. Excellent laws may be prohibited, and terrible laws may be constitutionally authorized. Any debate about whether a proposed government policy is good, bad, or indifferent ought to be moot until the proponents show the proposed law is authorized.

    When advocates, legislators, and judges claim with straight faces that “shall not be infringed” actually means “may be made a felony”, they leave us and our descendants open to other constitutional violations.

    If we refuse that respect for the Constitution, we are effectively condoning others, considerably less benign, who want do the same with other Constitutional protections. If we hold the Constitution in contempt, then we are giving our blessings to others who do the same.

    Whether we like it or not, the Framers were gun nuts. They had recently overthrown the legally constituted government, in part with privately owned weapons. If one reads what the Framers and ratifiers of the 2nd Amendment wrote and published at the time of the debates to inform the public about what they were doing, it is pretty clear that most of our current weapons laws (not just gun laws, but all individually carried weapons) are likely constitutionally prohibited.

    When they wrote and ratified “keep and bear”, they really did mean own, possess, and walk around with weapons, and the militia clause shows beyond doubt that they meant military grade weapons, including those useful for training, or could substitute for military grade weapons.

    We may like that or despise that, but we ought to respect the rule of law sufficiently to abide by the Constitution, including going through the amendment process to repeal the 2nd Amendment, and replace it with one authorizing gun/weapon prohibition.

    Pretending that the 2nd Amendment says what it clearly does not only authorizes others to say the same about other Constitutional provisions, such as the 1st and the 5th. Are we sure we want to go there?

    There have already been legislative attempts at the federal level to make publishing certain political books a federal felony. Fortunately for us, those attempts were slapped down by Supreme Court justices who still respect the 1st Amendment. Would a court in 30 or forty years do it again if the judiciary generally held the Constitution in contempt?

    While we may decry a policy of allowing law-abiding adults to carry weapons on campus, is it the law-abiding we need most to worry about? Or should we be worrying more about the consequences of our own willingness to ignore the federal and state Constitutions when they stand in the way of our preferences?

  5. Kevin Baas says:

    There are SOOO many things wrong with that I’m not even going to bother.

  6. Tom Bosworth says:

    “There are SOOO many things wrong with that I’m not even going to bother.”

    You just did.

  7. Kevin Baas says:

    http://dictionary.reference.com/browse/bother

    verb (used without object)
    3.
    to take the trouble; trouble or inconvenience oneself:
    Don’t bother to call. He has no time to bother with trifles.

  8. Tom Bosworth says:

    “He has no time to bother with trifles.”

    So, shall we assume you are opposed to the Rule of Law? Constitutional law, that is.

    Or are you of the school which holds that your opinion that a law is good thereby makes it Constitutionally authorized? If you are, you may well be in the majority.

  9. Dave says:

    Put a cork in your asshole, Tom….it’s spewing nonsense again.

  10. Kevin Baas says:

    I don’t feel it worth my time bothering to enumerating all the things wrong with what you said above.

    Geez, work on your reading comprehension. That was immediately obvious from the first part of the sentence.

  11. Tom Bosworth says:

    Thanks to you both for leaving the inescapable impression that you are incapable of responding coherently, much less persuasively, to any opinion which differs from yours.

    Reasoned discourse is not you strong suite. I can see why you avoid it.

  12. Kevin Baas says:

    Houston, we have a troll!

  13. Casey says:

    Tom & Kevin

    Crazy idea here….if the two sides are so sure they’re right and the majority of citizens support them why not amend the constitution?

  14. Kevin Baas says:

    There’s no need to amend the constitution here.

  15. Casey says:

    Kevin- so are you fine with the thought that people have a constitutional right (not privilege) to arm themselves and their families with military grade weapons?

  16. Kevin Baas says:

    That’s a rather extreme interpretation of the 2nd amendment – military grade weapons. The original intent of the amendment was so that the government could raise a militia for the revolutionary war. There’s really no reason anyone would need assault rifles to “protect their families”, and in fact owning a gun or guns does more to jeopardize one’s family than protect it.

    But if you’re asking if I’m fine that law-abiding sane citizens can own guns. Yes, I’m fine with that. Everybody is fine with that.

  17. David says:

    Quote: “Without the United States, the correlation between guns and deaths becomes very weak (for those technically inclined the coefficient of determination drops from .49 to .04).”

    Responses: Seems to me there isn’t a correlation if one outlier skews the results. One of the criticisms of the Lott study is “A third concern is that the conclusions made are very sensitive to slight changes in time period, which states are included, the model chosen, and coding errors.”

  18. Casey says:

    Since the revolution is over is there no more reason to have 2nd amendment?
    You mention that there is no reason a person needs assault rifles to protect their families. I’d agree for the most part but the 2nd amendment was to ensure a free state by means of raising a militia. So it does seem to give people the right to keep and bear military grade weapons in order to fight in a militarily way to maintain their freedom.

    I get where you’re coming from and I agree that guns can be dangerous to a family. I own a few fire arms but because of my children I don’t keep them in my home anymore…not even for personal protection

  19. Bruce Thompson says:

    There has been considerable discussion in this forum of the 2nd Amendment and what it means. Here is what is says:
    “A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.”
    However, there is substantial disagreement about what it means. It goes without saying that we can’t ask the authors and they apparently left no minutes or other discussion that helps explain their thinking. My guess it was put get the support of a faction concerned about the threat of “the merciless Indian Savages” (in the words of the Declaration of Independence) with little if any discussion.
    Generally interpretations fall into two groups: The “individual right theory” emphasizes the wording about the right of the people to keep and bear arms.” The “collective rights theory” emphasizes the initial clause. Between 1939 and 2008 the Supreme Court adopted the collective rights theory. Since then a bare majority of the Court has moved towards the individual right theory, but not nearly as far as the NRA would like them to go. (On its headquarters, the NRA has chopped off the first part of the 2nd Amendment, in effect doing its own amendment to the 2nd Amendment.)
    One danger of allowing oneself to fall into the NRA (or other) bubble is that it leads to the false belief that there is only one way to interpret the Constitution.

  20. David says:

    Quote: “guns in the hands of law-abiding citizens reduces crime”

    Response: Of course it does, nobody wants to get shot. Don’t most mass murderers kill themselves before the police show up.

  21. David says:

    Of the 22% of murders not involving a family member or a personal connection, rationale thinking is prominent. Thieves and murderers use the element of surprise, they prey on the weak, they often commit crimes in areas residents won’t report crime and they have tools to assist: gun(s), bullets, magazines, etc – they are using rationale thinking.

    And if the 22% of victims were armed maybe they’d have a chance to level the playing field – most times it won’t matter because thieves are thinking rationally and have the upper hand. But the more of us that do conceal carry, the more rationale criminals will avoid crimes involving people.

  22. AG says:

    Sometimes people get TOO wrapped up in the statistics. They’re important to understand, fascinating by themselves and can be quite enlightening… but can not be the sole basis of decision making.

    For example, I think clearly the data shows us that the more socioeconomic challenges you face the more likely you are to use or be a victim of gun violence. My new proposal is that no poor people should be allowed to have guns. Problem largely solved.

  23. Kevin Baas says:

    “Of course it does, nobody wants to get shot. Don’t most mass murderers kill themselves before the police show up.”

    So it’s not so much that the mass murderers don’t want to get shot, then, but that they don’t want to get shot by somebody else… Sounds like a power thing, which I supposed makes sense, given the context.

    “guns in the hands of law-abiding citizens reduces crime”

    well now that’s tautological, isn’t it? if they don’t commit a crime (such as shooting somebody when their life is not endangered), then they’re law-abiding.

  24. Kevin Baas says:

    “Since the revolution is over is there no more reason to have 2nd amendment?” mmmm…. enlightenment philosophers such as hobbes would argue that the state should provide the protection, and should be checked by a separation of powers and elections, but they’d also add on to that that if it becomes destructive to the ends to which it is supposed to serve, then the citizens are duty-bound to alter or abolish it, and that this is in fact part of the contract. (since the breach of contract terminates it.)

    so i wouldn’t go so far as to say it’s not needed anymore. though countries that are for the most part gunless are doing pretty well, esp. on the homicide part. and i don’t think we’ll be in need of revolt anytime soon. i mean, the tea party republicans in congress are pretty crazy, but the system is still working despite that (well, i suppose that’s debatable, but we’re still not a despotism, lets put it that way.) but it seems removing the 2nd amendment would be a step in the direction of despotism.

    “You mention that there is no reason a person needs assault rifles to protect their families. I’d agree for the most part but the 2nd amendment was to ensure a free state by means of raising a militia. So it does seem to give people the right to keep and bear military grade weapons in order to fight in a militarily way to maintain their freedom.”

    well i think – i would hope – the courts and more rational heads in congress will heed more to practical considerations and consequences, rather than pedantically literal readings of a law written in the days of muskets. that is, indeed, their job as stated in their contract with the citizenry.

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