Wednesday, June 22, 2016

Mandatory Background Checks: Commonsense Gun Control?

“Everyone knows that mandatory background checks for all gun purchases is just ‘common sense.’”

It used to be common sense that heavier objects fall faster than light objects.  Then Galileo did something bizarre: experiments that demonstrated that common sense on this is wrong.

Fortunately we have run this experiment.  Eight states adopted mandatory background laws for either all firearms transfers or all handgun transfers between 1960 and 2012.  (Why those years?  Consistent and reliable murder rate data from the FBI starts in 1960.)  So if this is just common sense that such laws disarm criminals, wouldn’t you expect murder rates to fall (at least a little) in those states?

In the following graphs blue is the murder rate/100,000 people for each year.  The orange line shows the average for the five years before the mandatory firearms background check law took effect, and the five years after.  In some states, yes, murder rates fell.  Where you see an asterisk next to the state name, it means the change was statistically significant: likely the change was not random,.  All murder rate data comes from the FBI’s Uniform Crime Reports system.
But in a number of states, murder rates rose after the new law:

If mandatory background checks reduce murder rates, wouldn’t you expect to see murder rate reductions in all these states, or at least most of them?  I won’t argue that background check laws increased murder rates, but the benefits are shockingly subtle if present at all.  If you want all the technical details and footnotes go here.

There’s another experiment.  Gun control advocates have often argued that “the gun show loophole” allows criminals to buy guns.  A few years back, a group of social scientists, one of whom has supported gun control, decided to study the effects of gun shows on murder rates in the zip codes closest to gun shows in California and Texas.  California requires all gun show purchases to go through background checks; Texas does not.  If gun shows are a source of guns used in murder, Texas should show increases after gun shows.  Their conclusions?  They found, “no evidence to suggest that gun shows increased the number of homicides in California during our study period.”

Texas is wide open with buyers able to buy guns at gun shows without background checks.  They found “that in the two weeks following a gun show, the average number of gun homicides declines in the area surrounding the gun show. Aggregating across all gun shows in the state, we find that there are approximately 16 fewer gun homicides resulting from the 200 gun shows in the average year.”
Are mandatory background checks “commonsense gun control”?  Yes like heavy objects fall faster than light objects!
Clayton E. Cramer teaches history at College of Western Idaho as needed.


  1. Just quick looking at the graphs Clayton, something jumps out: The ones that passed the laws earlier (in the 1960's and 1970's) the murder rate increases, just like it was doing on average all over the country, and the opposite is true for those in the 1990's, when homicide was dropping after hitting its peak in the early 1990's.

    In other words, it wasn't universal background checks but the removal of tetraethyl lead as a gasoline additive:

    Thanks for doing the math for us, I will point to this when discussing UBCs online.

  2. Yes likely UBCs just don't have much impact on murder rates regardless of direction. And leaded gasoline's phase-out, pushed by that notoriously environmentalist Reagan Administration, probably helped.

  3. In Texas and everywhere else there is no "gun show loophole". Go to a gun show and check, just about everyone with a booth selling guns is a FFL holder. There may be some booths selling relics, pre-1899, but anyone who regularly goes to shows and sells guns would be deemed to be in business by the ATF and required to be licensed. FFL holders are required to do background checks. Gun shows generally have a back room for background checks. So people talking about gun show loopholes don't know what they're talking about, as most liberals talking about guns.

  4. jwlacy: If you go in with a rifle on your shoulder with a for sale sign you can legally complete the transaction in the parking lot.

  5. Nothing to do with gun shows. You could put the word out at work and sell to a co-worker. Private transactions do not require FFL. If the seller had reason to believe that the buyer could not pass a background check, the transaction would be illegal. By the way, I just bought a "Weapon of WAR" from a friend in a parking lot. Since said weapon was a M91/30 Mosin-Nagant, I don't thing I will be using it to shoot up any night clubs.

  6. Finnish night clubs? Or would that be too dangerous?