When should you trust the experts? That question has been the focus of much debate lately, especially given the poor track record of various "experts" regarding issues such as whether to invade Iraq.

One response to the question involves putting great emphasis on academic titles and institutional affiliations, as an antidote to the more obviously corrupt forms of supposed expertise, most vividly exemplified by rent-a-hack "resident scholars" employed by partisan think tanks, or professional expert witnesses who offer their services to the highest bidder.

The problem is that some of the very worst examples of untrustworthy experts are found at the most elite institutions. Consider an article in the September issue of Scientific American, titled "Can Fat Be Fit?"

Author Paul Raeburn puts forth the following claims: For decades, "thousands of studies" have suggested that being "even a little overweight" was a serious health hazard. Then, two years ago, a study by Katherine Flegal and others came to the "startling conclusion" that "mildly overweight (sic) adults had a lower risk of dying than those at healthy weights."

Fortunately, Raeburn finds two experts — Harvard Medical School professors, no less — to explain away this perplexing result. According to Meir Stampfer and Walter Willett, Flegal and her colleagues should be ignored, because their study contains an egregious mistake.

"It's complete nonsense, and it's obviously complete nonsense, and it's very easy to explain why some people have gone astray," Stampfer informs Raeburn. The authors' mistake, he says, was to include smokers and chronically ill people among the lean subjects in their study.

"When you get sick, you lose weight and you die," Stampfer explains. If the authors of the Flegal study had taken that factor into account, then they wouldn't have come to their shocking, practically unprecedented conclusion. The article continues unabated in this vein and ends by characterizing Willett as the voice of what Raeburn calls "state of the art" expert opinion. Willett advises readers to maintain a weight toward the low end of the "normal" range if they want to stay healthy.

I'm going to pay Raeburn the compliment of assuming he's an incompetent journalist rather than, for example, someone on the take from a maker of diet drugs.

A competent journalist would have called at least one of the paper's authors and would have discovered Stampfer's criticism was completely false. Flegal and her colleagues did control for smoking and pre-existing illness, they said so in their paper, and the supplemental data showing that doing so made no difference to their conclusions were published on the U.S. Centers for Disease Control and Prevention's Web site at the same time as the paper itself, as Stampfer and Willett are perfectly well aware. (Raeburn never attempted to contact any of the various people whose work his article impugns.)

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A competent journalist would have done the modest bit of research necessary to discover that the Flegal paper's conclusions are no different from those of countless other studies. The paper is particularly important because of its statistical rigor and the unusually high quality of its data, but to anyone familiar with the medical literature its conclusions are about as startling as the conclusion that cigarettes cause lung cancer.

A competent journalist would have discovered that the paper's authors are all very distinguished scientists, that their paper won the CDC's highest award a year after Willett and Stampfer first made their dishonest criticisms of it, and that it remains the single most-cited paper published that year in what is one of the world's most prestigious medical journals.

One last detail: A competent journalist might have considered asking Willett how close he's come to following his own expert advice about maintaining what Willett claims is a "healthy" weight. You can guess the answer to that one.


Paul F. Campos is a law professor at the University of Colorado and can be reached at Paul.Campos@Colorado.edu.

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