Originally posted November 2, 2016.
Last week I introduced you to a piece by Robert Verbruggen explaining the flaw in a study of violence involving firearms by the Center for American Progress (a liberal progressive think tank). Verbruggen continued his exploration of research involving guns and crime here. In his second piece he addresses an academic paper written by Gary Kleck, Tomislav Kovandzic, and Jon Bellows.
Of the three studies I’ll be looking at in this series, this is arguably the most complicated. Instead of looking at the 50 states, it looks at every city in America with a population of 25,000 or more—1,078 in all. Instead of collapsing all gun-control laws onto a single scale, it separately measures the effects of 19 specific laws. And instead of just comparing raw crime rates, the authors build elaborate models that account for demographic and cultural differences between the cities, and that also include gun ownership so we can be sure the results stem from the laws themselves, rather than just reflecting the fact that states with strong gun cultures tend to have less gun control.
The key findings:
- As Kleck and co-authors have found in other studies as well, gun ownership by itself does not cause higher crime rates. This finding relies on some arcane statistics, unfortunately—the authors measure gun ownership through a “proxy” (the percentage of suicides committed with guns), and in addition employ a technique called “instrumental variables” to separate correlation from causation.
- Most gun-control laws don’t work. There’s even some (weak) evidence that a few of them increase crime.
- A couple laws do seem to reduce crime, however—most notably, requiring a license to possess a gun, a measure strongly opposed by gun-rights groups. The authors note that such laws entail background checks on prospective gun owners.
All of that squares with my own prior views, so I’m tempted to just agree with the study and leave it at that. But in my first post I promised nitpicking, and I shall deliver. Fortunately, nitpicking this study is easy to do, because the authors themselves are very thorough in explaining its limitations.
If this is the most complicated study we’ll be looking at this week, it’s also the ugly duckling in some ways. Perhaps the oddest thing about it is that it relies on data more than a quarter-century old, from 1990. The authors do this because good suicide data (which they used to estimate gun ownership) are not available at the city level in more recent years.
A lot has changed since 1990, though; crime has plummeted, and we’ve seen developments in federal law (such as the requirement for all licensed gun dealers to perform background checks and the creation of a system for performing those checks). It’s hard to say for sure how well the findings translate to the 2016 context. And by using a single year of data, the authors miss an opportunity to compare crime rates before and after the laws at issue went into effect, though in one of their models they do control for the 1980 crime rates of these cities, a somewhat similar idea.