Background Checks and Homicides
If retail gun purchase background checks are any indication, sales of guns may keep some crime down.
The Bureau of Justice Statistics (BJS) recently released a report 1 on background checks. Though not every state was covered, the 40 reported gives of an unexpected view into homicides and recent gun sales.
But before we dive in, here is the list of caveats:
- Only looks at 2016/7 data, so a snapshot in time.
- Gun sales may lag behind changes in local violence, so there is an unspecified lead/lag issue.
- Since the BJS also tells us that a minimum of 40% of crime guns come from street sources (not subject to background checks), looking at retail checks and crime might produce weak results anyway.
Up, Up and Away
Between 1999 and 2017, the U.S. population rose 16% while the number of background checks for gun purchases rose 99%. Clearly, America has been arming itself. Interestingly, all manner of crime, including violent crime, dropped during most of that period.
Also of interest is that the percent of rejected background checks has been declining. In 1999, 2.4% of background checks cancelled a sale, and by 2017 that was down to 1.4%, with a steady stepwise decline in between.
As the Gun Facts project has noted before, there was a 3% shift of crime guns from retail outlets to street sources before and after the national background check system came to life. Attrition might be driving street sources to be the first choice among thugs.
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First, we looked at the per capita rate of gun purchase background checks (checks per 100K adult population) and the overall homicide rate. We then did the same task but looked specifically at firearm homicides.
As you can see, there is a downward slope in homicides for higher rates of gun purchases. Now, there are many cultural factors that confound simple comparisons and are beyond this post. But as an acid test for guns in private hands and overall mayhem, there is no correlation (0.06 using a R2 test). In other words, higher guns sales not only do not lead to higher crime, crime tends to decline.
But this is for all forms of homicide – guns, knives, cars, etc. One might suspect that firearm homicides would tell a different story, but it did not. This is unsurprising, as most American homicides are committed with guns, so the variable (guns) in the second chart was also echoed in the first chart.
But it remains a curiosity that – generally speaking – the more retailing of guns in a state, the lower the homicide rate. This finding goes against some common political talking points.
At the far left of each chart, we have the homicide poster child, Washington, DC. They have the lowest rate of gun sales and the highest rate of murder.
And they are not alone. Though it’s a mixed bag, we see notoriously anti-gun states (Maryland, New Jersey, Massachusetts as well as DC) with low gun sales rates and high homicide rates. Oddly, some pro-gun states (Alaska, Mississippi, Kentucky) also report low gun sales rates, though their homicide rates are low as well.
One hypothesis often hyped is that the “easy” availability of guns leads to more violence. Retail gun sales are a measure of “ease” of acquisition, so if the hypothesis held water (which it doesn’t), then a high background check rate would correlate to higher rates of violence. Yet, that is not the case.
For policy, facts beat theory. Herein we see theory taking a beating.
- Background Checks for Firearm Transfers, 2016-2017, February 2021 ↩