Correlation and Causation and Guns and Games

The Washington Post has an interesting article on the relationship between video games and gun violence. The TL;DR version is: There isn’t any, get over it. Here’s a helpful graphic. Notice how the datapoints fail to cluster along the hypothesized trendline.

Source: Washington Post

Source: Washington Post

The study they posted compared spending on video games in different countries, vs gun deaths in those countries. Leaving out China, a distinct social and governmental entity all its own, video game spending varies by a factor of almost three, from Germany to socially similar Netherlands. Gun deaths vary from near zero in the UK and Japan, to 0.5 per 100,000 in Canada, which is almost an outlier, because everyone else is down near 0.25. Except for the US, of course, which is a true outlier at 3.2 — for a country that spends less per capita than even Germany.

So, what are we to conclude? Outside of the US, culture doesn’t seem to drive video game spending. The Netherlands and South Korea top the charts. Outside of the US, culture doesn’t seem to drive gun violence. The United Kingdom and Japan are near the bottom, Canada and the Netherlands near what passes for a top.

What statisticians are constantly repeating is that correlation doesn’t prove causation, because there might be a third factor that we haven’t considered. So, I can show a correlation between the softness of an asphalt parking lot and the amount of ice cream sold, but I can’t claim that as proof that soft asphalt causes sales of soft ice cream. The unaccounted for variable is the heat of the summer day that drives both.

So even it we did find a correlation between video games and gun deaths, it might be that there is a third factor, like mental illness, or cultural estrangement, that drives both of these conditions.

On the other hand, I can say that lack of correlation creates a strong presumption of lack of causation. If I claim that solar eclipses cause plagues, and you look at two thousand years of solar eclipses and find that the overwhelming majority did not take place immediately before a plague outbreak, then it’s a pretty good bet that my hypothesis is wrong.

Science can’t really prove claims, no matter how strong the evidence, because a later test might show the claims to be wrong. What science can say is that theory x has passed every test we have set for it. What science can say is, theory y fell at the first jump, because its claims of correlation have been shown to be not true.

This, of course, won’t keep some Associations and some politicians from using the videogame excuse as a smokescreen. But when you read their claims, ask yourself, what is it they are smoking?

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One Response to “Correlation and Causation and Guns and Games”

  1. Kurt Kremer Says:

    The hard thing to show, I think, are webs of causality. I almost wrote chains but that’s like likening time to a river. The people I’ve met (thus a small sample) who hate violent video games are combat vets–although most were from previous generations that didn’t grow up with video games (from Vietnam back). Even though I occasionally play the cartoony variety (Borderlands, Dragon Age (swords instead of guns, but just as bloody), I try to keep it to a minimum. It becomes addictive and, as I’ve seen with my kids, a desensitizing agent. But the latter doesn’t make it easier to pull a real trigger–it just numbs the reaction (or seems to). People are looking for easy causality, and asking political questions (the public versions of those are always simple minded, making it look like the investigator is taking action). There are actions that can be taken at the federal level to promote a change in gun culture, from reducing risk (a minor reduction) by outlawing semi-automatic weapons (which are loose enough cannons in the hands of police) and requiring background checks for anyone buying a gun in any circumstance to more positive changes such as requiring gun owners and their families to take gun safety classes. Those kind of actions require people to have adult discussions, ask deeper questions, and knock off the “cold dead hands” bullshit. (Hmm, I’ve rewritten this comment 5 times and keep running one. I’ll let this one ride.)

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