Three Reasons Not to Believe in an Autism Epidemic

ABSTRACT—According to some lay groups, the nation is experiencing an autism epidemic—a rapid escalation in the prevalence of autism for unknown reasons. However, no sound scientific evidence indicates that the increasing number of diagnosed cases of autism arises from anything other than purposely broadened diagnostic criteria, cou-pled with deliberately greater public awareness and in-tentionally improved case finding. Why is the public perception so disconnected from the scientific evidence? In this article we review three primary sources of misun-derstanding: lack of awareness about the changing diag-nostic criteria, uncritical acceptance of a conclusion illogically drawn in a California-based study, and inat-tention to a crucial feature of the ‘‘child count’ ’ data re-ported annually by the U.S. Department of Education. KEYWORDS—autism; epidemiology; epidemic If you have learned anything about autism lately from the popular media, you most likely have learned—erroneously— that there is ‘‘a mysterious upsurge’ ’ in the prevalence of autis