July 26, 2012
Gun Control vs Murder/Crime rates: a statistical look

The recent movie theater shooting got me thinking about gun control and crime. The lunitic that shot all those people had an AR-15 with 100 round magazine, two pistols and a shotgun. Could more gun control have prevented it?

So I did some research and with a google search of “gun law vs crime scatter plot” I found (1st result) a wonderful article on gun control vs murder rates. It is a state by state analysis that plots the state’s Brady Score (higher = more gun control) against murder rates.

What makes the article so wonderful?

Math. And LOTS of it :)

It has the following data for all 50 states (except Florida, which does not submit the data for some reason):

  • Brady Score (how much gun control a state has)
  • Murder Rate per 100k population
  • Firearm murder rate per 100k population
  • Firearm Murder %
and I added
  • Violent Crime Rate per 100k population
The article lists all sources and (very detailed) goes over the process of creating this study. Since I added the violent crime rate, I’ll post the source: http://www2.fbi.gov/ucr/cius2008/data/table_05.html

He then uses a scatterplot to display the data. For math n00bs, let me tell you real quick what that is. You plot data points on a X/Y axis and see if there is any correlation. Here are some examples of correlation:

(1 is high positive correlation, -1 is high negative correlation, 0 is no correlation)



With guns vs crime, you might expect a linear relationship, like the top right one. More gun control = less crime, right?

Well this may surprise you.

Here are the scatter plots:




Notice the lack of correlation. No upward sloping line (no downward sloping line). No lines whatsoever.

So what does this tell us?

There is little or NO correlation (either way) between gun control and murder rate, firearm murder rate, firearm murder % and violent crime rate. Gun control does not increase crime, it does not decrease crime.

For a full analysis of this study, please visit the original article above. Also, feel free to look at the raw data by downloading the excel sheet.

Draw your own conclusions, but know that gun control has no effect on murder, gun murder or violent crime rates in the United States.