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Causal Friday: On The Public Health Implications Of Fifty Shades Of Grey…

February 13th, 2015 · 3 Comments
Causal Friday

With Fifty Shades of Grey coming out this weekend, I figured it was a good time for a reminder to be careful out there when doing it with models:

Sex toy injuries surged after ‘Fifty Shades of Grey’ was published

The number of Americans requiring emergency room care for injuries involving sex toys has approximately doubled since 2007, according to data from the Consumer Product Safety Commission. Much of that increase happened in 2012 and 2013, following the release of the wildly popular erotic novels in the Fifty Shades of Grey series. And the overwhelming majority of these injuries — 83 percent — require “foreign body removals.”

So do we need to be thinking about the negative public-health externalities of this particular phenomenon? I get the feeling that the headline writer chose her words carefully, but the article itself (and others like it) seem to reallllly want me to think, despite an offhand sentence to the contrary, that the increase in injuries is actually because of the book (or at least that the increase in injuries is a result of the increase in sex toy use that resulted from the publication of the book). But we nerds know better…

This suggestion is a particular form of the correlation versus causation issue known as the “post hoc ergo propter hoc” fallacy (not to be confused with the second episode of The West Wing)- namely, that just because one thing happens after another doesn’t imply that the latter happened because of the former. In this instance, we see a claim that sex toy injuries increased after the book was published, but we can’t conclude that the increase happened because of the book itself.

The fallacy is highlighted further when a more complete dataset is observed:

Now it is more clear that the increase was largely following what appears to be a longer term trend- in fact, the data suggest that perhaps the relationship goes in the other direction and the increased proliferation of sex toys and sexual experimentation lead to the book being published and getting so popular.

It’s worth keeping in mind, however, when causality matters and when it doesn’t- for example, my warning to be careful is relevant regardless of what is causing the increase in injuries. Also, having this data makes this scenario a tad less surprising:

Given the 87 percent figure mentioned in the article, I’m actually kind of surprised that this didn’t show up on the board.

Tags: Causal Friday

3 responses so far ↓

  • 1 lance // Feb 13, 2015 at 6:56 pm

    Douglas Adams on causality:

    “Anything that happens, happens.

    Anything that, in happening, causes something else to happen, causes something else to happen.

    Anything that, in happening, causes itself to happen again, happens again.

    It doesn’t necessarily do it in chronological order, though.”–DNA

  • 2 Syed // Feb 14, 2015 at 6:33 am

    Nice analysis, the way you explain things and relates to Economics is very interesting.

  • 3 Sami // Apr 22, 2015 at 9:55 am

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