In The Politics of Autism, I discuss the uncertainty surrounding estimates of autism prevalence.
At Scientific American, Darold A. Treffert takes a skeptical look at a recent CDC report suggesting an autism prevalence of 1 in 59.
When the report came out, the headlines read along the lines of “Autism cases continue to rise: now 1 in 59 children have autism.” But let’s look at that CDC study more critically. It is based on an active surveillance system established in 2000 that estimates autism spectrum disorder (ASD) among children age 8 years living in 11 states.
Using that system, the prevalence of autism (ASD) rose from 1 in 150 children in 2000–2002, to 1 in 68 children during 2010–2012 and 1 in 59 children in 2014. That means the prevalence of autism more than doubled in the 12-year period between 2000 and 2012 and increased nearly 16 percent just in the two-year period between 2012 and 2014.
That is preposterous. From 1 per 150 children to 1 per 59 children with autism in slightly more than a decade? No wonder headlines speak of an “epidemic.” Are these believable figures, or might it be because we keep diluting the condition and expanding the definition, and in so doing we keep moving the goalposts? I believe that to be the case.
There are problems that cast doubt on that method and those numbers for actual prevalence of ASD. Figures include “educational autism,” which is a diagnosis made by teachers or educational specialists in the classroom and “medical autism,” based on review of available medical records. There are no actual in-person evaluations. Casting more doubt is the fact that the prevalence in one state, Arkansas, was 1.31 percent but more than double that in another, 2.93 percent in New Jersey. The prevalence in Wisconsin rose 31 percent between 2012 and 2014. Is that a believable actual increase in ASD in two years in Wisconsin?