Antivaccine nonsense Autism Complementary and alternative medicine Medicine Pseudoscience Quackery Skepticism/critical thinking

Epi Wonk versus the Geiers, part II

Epi Wonk has completed part II of her deconstruction of the latest abuse of epidemiology and statistics by those pseudoscientists for the mercury militia, Mark and David Geier. (I commented on part I here):

Pretty steep slopes and, therefore, apparently strong associations. But there’s no attempt to control for, or adjust for, the confounding effect of birth cohort. Just one look at Figure 1 (or a basic knowledge about trends in autism) tells you the regression coefficients (slopes) are being driven by increases in autism risk over time. Given the increase in frequency of autism (and other neurodevelopmental disabilities) during time time period, you could do an ecological regression analysis of almost any factor that varied over time and you would find an an association with autism. I would bet that you could enter number of sushi bars per capita into an ecological regression and you’d find an association with autism rates.

I once pointed out this very thing about the way antivaccinationists abuse correlation as causation, in this case starting at 1983 as the baseline, and facetiously said:

A lot of other things have happened since 1983 as well. For example, in the early 1990s, the diagnostic criteria for autism were broadened, and campaigns for greater awareness were begun. Diagnoses of autism in 1983 were made using the DSM-III, where the criteria for an autism diagnosis were much more restrictive than those in the DSM-IV, released in the early 1990s. Moreover, in 1983, categories of Asperger’s and pervasive developmental disorder-not otherwise specified, both of which are lumped into the 1 in 150 figure for 2008, weren’t recognized in the DSM-III. Of course, if I wanted to be snarky (and perish forbid that I would ever be snarky), I could point out that 1981 was the year that the IBM PC was released, followed by the Apple Macintosh in 1984, both of which led to the exponential growth of households owning and using personal computers. That’s it! It must be computer use that led to the increase in autism in the 25 years since 1983! Wait, what about the compact disc? It just so happens that 1983 is the year that the CD was first released in the American market. Ergo, it must be CDs that cause autism.

I can’t wait until part 3.

By Orac

Orac is the nom de blog of a humble surgeon/scientist who has an ego just big enough to delude himself that someone, somewhere might actually give a rodent's posterior about his copious verbal meanderings, but just barely small enough to admit to himself that few probably will. That surgeon is otherwise known as David Gorski.

That this particular surgeon has chosen his nom de blog based on a rather cranky and arrogant computer shaped like a clear box of blinking lights that he originally encountered when he became a fan of a 35 year old British SF television show whose special effects were renowned for their BBC/Doctor Who-style low budget look, but whose stories nonetheless resulted in some of the best, most innovative science fiction ever televised, should tell you nearly all that you need to know about Orac. (That, and the length of the preceding sentence.)

DISCLAIMER:: The various written meanderings here are the opinions of Orac and Orac alone, written on his own time. They should never be construed as representing the opinions of any other person or entity, especially Orac's cancer center, department of surgery, medical school, or university. Also note that Orac is nonpartisan; he is more than willing to criticize the statements of anyone, regardless of of political leanings, if that anyone advocates pseudoscience or quackery. Finally, medical commentary is not to be construed in any way as medical advice.

To contact Orac: [email protected]

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