Does increased gun ownership in the US correlate with a reduction in violent crime rates?

Question

This is somewhat of the converse of the question Is Gun Control Effective:

A quote of famous musician and gun advocate Ted Nugent has been making the rounds on the Internet again lately:

Where you have the most armed citizens in America, you have the lowest violent crime rate. Where you have the worst gun control, you have the highest crime rate.

Do larger numbers of legally armed citizens correlate to lower violent crime rates?

I'm not as interested in the converse portion of his quote, as the effectiveness of gun control is covered under the question I linked earlier. Instead, I'm looking for any evidence that an increase in private gun-ownership acts as a deterrent for violent crimes within a given geographic region.

Answer 1

In order to answer this question, I don't see any reason to restrict ourselves to comparison between states. The variation in gun laws between states are quite small, and the ease of crossing state boundaries make it easy for crime to flow across those borders. Instead lets look at comparison between countries, where there is marked different in gun laws and less likelihood of cross-border crime. Fortunately there is a study by Mark Reid, a machine learning researcher at Australian National University that does exactly that.

The graph is for OECD countries, i.e. those with reasonably developed economies. There is a clear correlation between gun ownership and gun deaths. The outlier of Mexico is due to an ongoing drug war

of course gun deaths covers a lot of things other than homicides, including suicide, and it is possible that the prevalence of guns causes people to use a gun for a suicide that they would use something else for if it wasn't available. So let's restrict the analysis to gun homicides.

Again Mexico is the exception, but so is the US. It has a much higher level of gun ownership and gun homicide than any of the other countries. So much so that it obscures any trends in the graph. Let's replot without those two countries.

Now the trend is much less pronounced, but still detectable (especially if you consider Israel a special case, given its ongoing conflict). Without Israel there are certainly few countries with low gun ownership and high gun homicide. And it's probably worth restating that the US has rates of both gun ownership and gun homicide more than double any other country on that chart.

EDIT: I haven't been able to make a chart, but the figures for all homicides (more than just gun-related) follow a similar pattern to gun-related homicides. The US has double the homicide rate of the next highest country in the OECD, and four times the rate of most (with the strange exception of Luxembourg, whose homicide rate is very slightly higher than half the US).

EDIT:Several people commented that the questions was asking about violent crime, not just homicide. I found what look like reasonable figures for assaults at Nationmaster Encyclopedia . Plotting those against gun ownership gives this graph:

The US is the data point at the top centre of the chart.

Now it appears that high gun ownership is not correlated with high levels of assault. But that wasn't the claim. The claim was that high gun ownership reduced levels of violent crime. This graph certainly indicates there is no inverse correlation between gun ownership and assaults.

Answer 2

UPDATE 4/4/2013:

The claim is somewhat supported by graphing the US Census Bureau's 2006 Violent Crimes Data and the "Gun Rights Index" calculated here:

But, statistically, the correlation is very weak.

Here is the data I used, scraped from the cited sites:

data = {
{Alabama, 425, 6.8},
{Alaska, 688, 8.0},
{Arizona, 501, 9.3},
{Arkansas, 552, 6.2},
{California, 533, 4.9},
{Colorado, 392, 7.7},
{Connecticut, 281, 5.1},
{Delaware, 682, 6.3},
{Florida, 712, 6.5},
{Georgia, 471, 7.1},
{Hawaii, 281, 2.6},
{Idaho, 247, 8.7},
{Illinois, 542, 3.0},
{Indiana, 315, 6.8},
{Iowa, 284, 5.8},
{Kansas, 425, 7.4},
{Kentucky, 263, 7.4},
{Louisiana, 698, 6.9},
{Maine, 116, 7.4}, 
{Maryland, 679, 5.1},
{Massachusetts, 447, 3.7},
{Michigan, 562, 6.3},
{Minnesota, 312, 6.1},
{Missouri, 546, 7.4},
{Montana, 254, 8.7},
{Nebraska, 282, 7.4},
{Nevada, 742, 7.4},
{New Hampshire, 139, 7.4},
{New Jersey, 352, 4.1},
{New Mexico, 643, 7.4},
{New York, 435, 4.6},
{North Carolina, 476, 6.9},
{North Dakota, 128, 6.2},
{Ohio, 350, 7.4},
{Oklahoma, 497, 6.2},
{Oregon, 280, 7.4},
{Pennsylvania, 439, 7.4},
{Rhode Island, 284, 4.6},
{South Carolina, 766, 6.3},
{South Dakota, 171, 8.7},
{Tennessee, 760, 8.1},
{Texas, 516, 6.8},
{Utah, 224, 7.5},
{Vermont, 137, 8.0},
{Virginia, 282, 6.9},
{Washington, 346, 6.7},
{West Virginia, 280, 7.4},
{Wisconsin, 284, 6.2},
{Wyoming, 240, 8.7}
}

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This is really a comment on @RedGrittyBrick's answer, but I do not know how to put graphics in a comment...

The claim is not supported by the data provided by @RedGrittyBrick (which are incomplete -- note FL's lack of gun crime data, which is a pretty important data point)...

Here's the plot of "Gun Murders / 1M Population" vs "Gun Ownership %":

And the linear model parameter table:

This is totally back-of-the-envelope stuff, I haven't checked the sources, I don't assert a logical connection between "% gun ownership" and weaker gun laws, I'm dubious about the logical connection between "gun murders" and all gun crime, I shudder at the use of "The Guardian" as a primary source, etc.

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_{Edit by RedGrittyBrick (I've now deleted my "Answer")}

The data came from US Liberals, The Guardian, ipl for kids but primary data sources were claimed to be

• Gun ownership by state, 2007 USA Carry
• Gun crimes by state, 2011 FBI Uniform Crime Reports
• Population by state, 2010 2010 census

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