Confessions of a Quackbuster

This blog deals with healthcare consumer protection, and is therefore about quackery, healthfraud, chiropractic, and other forms of so-Called "Alternative" Medicine (sCAM).

Saturday, July 02, 2005

US Department of Education Data on "Autism" Are Not Reliable for Tracking Autism Prevalence

US Department of Education Data on "Autism" Are Not Reliable for Tracking Autism Prevalence
James R. Laidler, MD

From the Department of Biology, Portland State University, Portland, Oregon


Many autism advocacy groups use the data collected by the US Department of Education (USDE) to show a rapidly increasing prevalence of autism. Closer examination of these data to follow each birth-year cohort reveals anomalies within the USDE data on autism. The USDE data show not only a rise in overall autism prevalence with time but also a significant and nearly linear rise in autism prevalence within a birth-year cohort as it ages, with significant numbers of new cases as late as 17 years of age. In addition, an unexpected reduction in the rise of autism prevalence occurs in most cohorts at 12 years of age, the age when most children would be entering middle school. These anomalies point to internal problems in the USDE data that make them unsuitable for tracking autism prevalence.


Key Words: autism • prevalence • education

Abbreviations: USDE, United States Department of Education • IDEA, Individuals With Disabilities Education Act • DSM-IV, Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition • OAR, Oregon Administrative Rules

The prevalence of autism and whether that prevalence is rising are 2 of the many controversies surrounding this disorder. Much of the controversy is attributable to the difficulty of finding good data. A number of studies have examined the prevalence of autism and related disorders1–6 in a number of different populations and periods. However, all of these studies are constrained by time and funding to examining either a relatively small population or relatively few points in time.

Many autism advocates have used data from the United States Department of Education (USDE) in their presentations to lawmakers7 and the public to show a dramatic and accelerating rise in the prevalence of autism in the United States. Because these data are being used to influence public policy, it is critically important to know if they can be used to reliably measure the prevalence of autism.

This study examined the autism data collected by the USDE by following individual birth-year cohorts through time. It also examined the methods used to collect the USDE autism data and compared those with the methods used by medical practitioners to diagnose autism.

(There's more....)