In case you haven’t heard, Internet blogger Denise Minger published a statistics-based scathing review of the China Study (found here at http://rawfoodsos.com/2010/07/07/the-china-study-fact-or-fallac/-305). This has, as expected, created some heavy debate.
If you haven’t been around the Internet much yet, people on the Internet are famous for their bad manners. Because people aren’t actually present with and having to look at others, they feel justified in making rude, belligerent, personally offensive comments that they would NEVER make in “real” life.
As with any diet/nutrition debates, part of the rancor, is from the militant attitude many take to defending their viewpoints. If you haven’t seen many food debates, it’s plain to see that vegans tend to be exceptionally aggressive in defending their beliefs. Unfortunately this isn’t confined to vegans, studies have shown this to be a fairly universal human trait. When presented with data that agrees with our beliefs we tend to accept it uncritically, “of course that’s true. That totally makes sense.” When presented with data that disagrees with our beliefs we tend to reject it uncritically, “there’s no way that COULD be true. There were a lot of errors, it’s not worth my time to even look at it.” This is something we all have to be aware of and watch for in ourselves.
A good deal of the criticism of Denise Minger’s work has revolved around the statistics she used to analyze the data. This typically falls into two critiques. The first is intellectual snobbery, “she has no degree nor the ‘proper’ credentials, her work COULDN’T POSSIBLY be up-to-par.” This is the mistake noted above, and unfortunately is all too common in academic circles. This type of view is completely unscientific and anyone espousing it should not in good conscience call themselves a true scientist (and I would say this to someone in a face to face debate). The second critique is a fair questioning of her methods and is a normal part of peer review in the scientific process.
Denise’s response:
“It seems the main criticisms against my review so far are that I’m using raw data and univariate correlations. This misses the point completely, as I’m trying to point out that it’s Campbell whose claims, in every single instance, align perfectly with the raw data but become erroneous once major confounders have been adjusted for. I’ll try to explain this point better in my reply, as perhaps I didn’t make it clear enough in the critique.
In addition, as I’ll explain in my reply, univariate correlations weren’t the only ones I used in my analysis — they’re just the only ones I chose to include in this post. I felt they’d be effective for getting my message across to a standard audience who may not be too interested in stats jargon, since they’re a simple way to illustrate the effects of confounding variables and they’re easy to graph visually. I also ran multiple variable regressions on the data I used and it corroborated with what I achieved through the more “crude” methods highlighted in this critique. In the not-too-distant future, I’ll be writing a separate post with the results of these regressions — and maybe including downloadable spreadsheets with some data, so any skeptics can test for themselves what I’ve done.”
While these second kind of criticisms are appropriate and may have validity, it is important to recognize that they hold equally well to Campbell’s work. As one commenter to the post said:
“I guess what I’m saying is that I’m unconvinced that this data set deserves all the attention it’s been given. I think Minger’s analysis is good in that it points out the shortcomings of “The China Study”, but it should NOT be used (and I believe she would agree) to argue the opposite point. In the same way that the data doesn’t really support the assertion that an all-plant diet is healthy, neither does it support the assertion that an omnivorous, high-meat, or any other type of diet is healthy.”
And that is the ultimate point. To all those who go about bludgeoning people with the book the China Study to PROVE that a vegan diet is healthy and that an omnivorous diet will cause cancer and heart disease, please stop. Whether you believe Denise Minger’s re-analysis of the data is flawed or not, she has poked enough holes in Campbell’s analysis to render it useless. The China Study does NOT PROVE ANYTHING. Denise Minger has shown that be excluding cofounders that the data might actually suggest (not prove) that meat might be protective and wheat might be harmful. But as I attempted to point out in my last post, her analysis is at best correlation and does not prove anything either.
Being the Internet and all, it is likely that neither side will admit anything and this “debate” will continue on and on. I agree that the China study has been given far more attention that it deserves, and unless something really noteworthy comes up, this is the last blog post I intend to spend on it.