It’s been a while, i know. So something dramatic must have happened. Multiple dramatic things have happened, but one in particular drove me to dust off my WP login. This article on obesity has been rapidly making the rounds (i’ve seen it linked no less than a dozen times since yesterday afternoon). It’s got lots of interesting information in it and easily quotable lines. But in virtually every single cite i’ve seen of it so far (on Facebook, news articles, etc.), the same finding has been quoted as the most striking punchline of the article, but has, in every case misrepresented what that finding actually is. The line from the article that matters is this (from the abstract):

North America has 6% of the world population but 34% of biomass due to obesity.

The quotes of that finding i’ve seen thus far however have inevitably been framed as:

North America has 6% of the world population but 34% of biomass.

A seemingly innocuous edit, but resulting in a complete misrepresentation of what the study actually found. What the analysis shows is that if you limit the analysis only to account for the obesity in the world (i.e., we look only at the “excess” weight) on the planet, N. America accounts for 34% of that amount. Not 34% of all biomass. In order for the citation as it’s making the rounds to be true, the average N. American would have to weigh 371 kg (or roughly 818 pounds; calculations stem from Table 3 in the paper). Now part of the problem is the way things are written as most people aren’t used to having to do a little simple math to digest their research blurbs, but sometimes it’s completely necessary to be sure you aren’t completely lead astray.

Now, i’m not trying to diminish the findings in the article, as i think they have done a good job of demonstrating how weight is unevenly distributed across the globe. Just not in the way people are saying they’ve said it is.


5 Responses to ugh!!!

  1. I noticed this error in The Daily‘s write-up and joked that the editor was one of those people who thought algebra has no practical application. They’ve since corrected it by adding the word “excess” in several places.

  2. bill says:

    “North America has 6% of the world population but 34% of biomass.”

    The misrepresentation is so bad that it’s actually funny.

  3. jimi adams says:

    It would be funnier if people didn’t seem to so earnestly believe it. Luckily, somewhere later in that day or early the next most seemed to start picking up on the difference and get it right.

  4. […] day after the BMC Public Health article was published, a post (“ugh!!!”) on the blog Permutations complained about the constant misquotes of the study, but this did little […]

  5. […] There have been many examples of bloggers flagging up critical flaws in published papers (and flaws in media attention), and on a regular basis, retractions are covered in the excellent Retraction Watch blog. Whether […]

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