Analysis of gun laws and violent crime

I’ve done previous analyses on the Brady scoring for various gun laws and how they relate to suicide rates in various States. To briefly recap previous articles, stronger gun laws overall don’t make much of a difference in whether a State has a lower suicide rate.

Now I’m going to take a look at violent crime and gun laws. Since a significant portion of vioelnt crime is committed with a firearm, having stronger gun laws should translate into lower violent crime rates. Or that is the assertion.

For the violent crime rates, I’m using the FBI Uniform Crime Report for 2016, specifically Table 3. Since the Brady Campaign never scored Puerto Rico and Washington, DC, those are excluded from this analysis. The Brady score is along the X-axis, violent crime rate per 100,000 along the Y-axis. I used the raw scoring, not the “curve” scoring, to avoid any bias.

That looks pretty well all over the place.

And the regression score is -0.0184. Virtually no measurable correlation. Gun laws, or at least how the Brady Campaign has scored them, largely do not make a difference in the violent crime rates for the State.

But that isn’t the end of this analysis. The FBI Uniform Crime Report separates out the violent crime rates for metropolitan areas, cities outside the immediate metropolitan area, and non-metropolitan counties. Let’s start with the Metropolitan Statistical Area.

The one outlier in the upper left is Alaska. And this again looks all over the place. Virtually no correlation as well with a regression score of -0.0304. Take out Alaska and it’s super high crime rate, and the regression falls to -0.0153. In both cases, it’s clear that gun laws don’t make a difference with regard to violent crime in metropolitan areas.

Next are Cities Outside Metropolitan Areas. Delaware, New Jersey, Hawaii, and Rhode Island from this analysis due to non-reporting of necessary data.

And in this chart, the outlier all the way at the upper left is Arizona. And that really skews the regression, putting it at -0.0356. Still low enough to say confidently there is no correlation here to be had, though just the look if the chart shows this. Remove the outlier and it becomes -0.0277.

Last is Non-metropolitan Counties. Delaware, Rhode Island, and New Jersey are again excluded due to non-reporting. Non-metropolitan counties are going to include small towns and largely rural areas. Two ready examples are Clarke County, Iowa, and Nemaha County, Nebraska, two counties in which I’ve previously resided.

And again, no obvious correlation from the graph. And no significant outliers this time. Regression score is -0.0334. The strongest of the regressions when accounting for outliers in the previous categories, but still so small that we can basically say there is no correlation.

So the state of a State’s gun laws is not a predictor in whether a State has a low or high violent crime rate. The data do not support the claim that stronger gun laws will result in lower violent crime rates.