While examining Guns And States, Scott Alexander drifts into gun ownership in different countries:
According to MA&H 2007, each absolute percentage point in gun ownership was related to a 2.2 relative percentage point difference in homicide. This part of the study was beyond my ability to check, and I’m not sure why they switched from absolute to relative percents there, but suppose we take it seriously.
America has a gun ownership rate of 32%, so if we somehow decreased that to zero, we would naively expect about a 70% decrease in homicides. Unfortunately, only 67% of American homicides involve guns, so we’re back to pretending that eliminating guns will not only have zero substitution effect but also magically prevent non-gun homicides. This shows the dangers of extrapolating a figure determined by small local differences all the way to the edge of the graph.
Maybe we can be more modest? Canada has a gun ownership rate of aboot 26%, so…
…wait a second. I thought we’ve been told that the US has a gun ownership rate seven zillion times that of any other country in the world, and that is why we are so completely unique in our level of gun crime? And now they’re telling us that Canada has 26% compared to our 32%? What?
Don’t trust me too much here, because I’ve never seen anyone else analyze this and it seems like the sort of thing there should be loads of analyses of if it’s true, but I think the difference is between percent of households with guns vs. guns per capita. US and Canada don’t differ very much in percent of households with guns, but America has about four times as many guns per capita. Why? I have no idea, but the obvious implication is that Canadians mostly stop at one gun, whereas Americans with guns buy lots and lots of them. In retrospect this makes sense; I am looking at gun enthusiast bulletin boards, and they’re advising other gun enthusiasts that six guns is really the bare minimum it’s possible to get by with (see also “How many guns can you have before it’s okay to call your collection an ‘arsenal’?”, which I have to admit is not a question that I as a boring coastal liberal have ever considered). So if the guy asking that question decides he needs 100 guns before he gets his arsenal merit badge, that’s a lot more guns per capita without increasing percent household gun ownership. This should actually be another argument that guns are not a major factor in differentiating US vs. Canadian murder rates, since unless you’re going on a mass shooting (WHICH IS REALLY RARE) you wouldn’t expect more murders from any gun in a household beyond the first. That means that the small difference between US and Canadian household percent gun ownership rates (32% vs. 26%) would have to drive the large difference between US and Canadian murder rates (1.4 vs. 3.8), which just isn’t believable.
…okay, sorry, where were we? Canada has a gun ownership rate of about 26%, so if America were to get its gun ownership as low as Canada, that would be -6 absolute percentage points = a 13% relative decrease in murder rate = the murder rate going from 3.8 to 3.3 = a 0.5 point decrease in the murder rate. That’s pretty close to the difference between our 2.1 US-sans-culture-of-violence estimate and the 1.4 Canadian rate – so maybe beyond the cultures of violence, the rest of the US/Canada difference really is due to guns?
(I’m not sure whether I should be subtracting 13% from 2.1 rather than 3.8 here)
In Germany, 9% of households own firearms (wait, really? European gun control is less strict than I thought!) Using MA&H’s equation, we predict that if the US had the same gun ownership rate as Germany, its murder rate would drop 50%, eg from 3.8 to 1.9. Adjust out the culture of violence, and we’re actually pretty close to real Germany’s murder rate of 0.8.
How much would gun control actually cut US gun ownership? That obviously depends on the gun control, but a lot of people talk about Australia’s gun buyback program as a model to be emulated. These people say it decreased gun ownership from 7% of people to 5% of people (why is this number so much lower than Canada and Germany? I think because it’s people rather than households – if a gun owner is married to a non-gun-owner, they count as one gun-owner and one non-owner, as opposed to a single gun-owning household. The Australian household number seems to be 19% or so). So the gun buyback program in Australia decreased gun ownership by (relative) 30% or so. If a similar program decreased gun ownership in America by (relative) 30%, it would decrease it by (absolute) 10% and decrease the homicide rate by (absolute) 22%. Since there are about 13000 homicides in the US per year, that would save about 3000 lives – or avert about one 9/11 worth of deaths per year.
(note that our murder rate would still be 3.0, compared to Germany’s 0.8 and Canada’s 1.4. Seriously, I’m telling you, the murder rate difference is not primarily driven by guns!)
Is that worth it? That obviously depends on how much you like being able to have guns. But let me try to put this number into perspective in a couple of different ways:
Last time anyone checked, which was 1995, about 618,000 people died young (ie before age 65) in the US per year. Suppose that the vast majority of homicides are of people below 65. That means that instituting gun control would decrease the number of premature deaths to about 615,000 – in other words, by about half a percentage point. I’m having to borrow this data from the UK, but if it carries over, the average person my age (early 30s) has a 1/1850 chance of death each year. Gun control would decrease that to about 1/1860. I’m very very unsure about the exact numbers, but it seems like the magnitude is very low.
On the other hand, lives are very valuable. In fact, the statistical value of a human life in the First World – ie the value that groups use to decide whether various life-saving interventions are worth it or not – is $7.4 million. That means that gun control would “save” $22 billion dollars a year. Americans buy about 20 million guns per year (really)! If we were to tax guns to cover the “externality” of gun homicides preventable by Australia-level gun control, we would have to slap a $1000 tax on each gun sold. While I have no doubt that some people, probably including our arsenal collector above, would be willing to pay that, my guess is that most people would not. This suggests that most people probably do not enjoy guns enough to justify keeping them around despite their costs.
Or if all gun enthusiasts wanted to band together for some grand Coasian bargain to buy off the potential victims of gun violence, each would have to contribute $220/year to the group effort – not totally impossible, but also not something I can really see happening.