Discussion about this post

User's avatar
José Duarte's avatar

Nice that you posted this.

Nate is too generous toward Montez, et al. (not to be confused with the solo Montez essay that Van Bavel and Knowles cited).

It's invalid and that it covers 50 states is irrelevant. Covering 50 states doesn't make something valid. It's invalid for the reasons I go into in my report. We don't know what their gun control variable is, because they don't tell us, it has things like "brady law" when that's a federal law in force since the late 90s, "assault weapon" ban when that was a federal law for a good chunk of their period, etc.

We don't know what most of their nine laws refer to, what the rubric was, what the state ratings were, or what it means to subtract zero from one, which is what they say they did.

There are more reasons it's invalid, like that they didn't control for race.

And as a reminder, they didn't actually find a general effect – Knowles lied about that. (This was the source he scrambled for as a fallback – they never cited it in their paper.) Their only effect was for women, which makes even less sense.

In fact, an effect for men, women, or general pop is mathematically impossible if we assume these arbitrarily chosen gun control laws affected life expectancy by reducing murder and/or suicide rates (it would have to be bottom line rates, not just via gun). Those would be the obvious implied pathways, but they never actually articulate a theory – not Montez, not Knowles. Gun laws won't reduce cancer or something, so it's got to be murder/suicide. But it turns out that even a chunky reduction of those wouldn't reduce life expectancy by anywhere near the 0.5 years they claim for women. (And women are much less likely to be killed with a gun anyway.)

There aren't nearly enough murders and suicides to drive such an effect, so no dice. The action is elsewhere. This is outlined in my report, with the life table example.

You guys all pretty much do that thing where you treat a published study as being valid by default, wanting to be nice to the authors, collegial, etc. No, just because something is published doesn't mean it carries any inherent validity or epistemic standing. The Montez, et al. study is nothing, has no standing. We can't do anything with it. If we don't know what someone did, if we can't see what they did, their ratings, data, etc. and they made big errors from what we can see, that's not anything. It shouldn't have been published and it's just polluting the literature and our brains.

As far as your search for "gun" in their paper, try "firearm(s)". It won't help them much, but that's where their false claim is, where they cite the Montez essay.

Expand full comment
Doctor Hammer's avatar

It is kind of shocking they neglected to include demographics. I would think that would be the prime driver, not just race but age and such. I'd have thought that per capita income, race categories and some age distribution ranges would be obvious first choice controls one would include, but maybe that's just an economist thing.

Expand full comment
11 more comments...

No posts