The administrative prevalence of autism in Nevada schools increased from an average of one in 3,750 students in 1995 to one in 422 in 2004, according to new research conducted by ºÚÁÏÍø's Department of Political Science and School of Public Health. It is the first comprehensive study of its kind in Nevada.
The ºÚÁÏÍø study defines administrative prevalence as the number of children ages 6-17 (as a share of total enrolled student population in grades 1-12) who were diagnosed by school authorities as having autism or autism spectrum disorder (ASD) and who receive special education services under the Individuals with Disabilities Education Act (IDEA).
The data was collected from all 17 school districts in Nevada for years 1995-2005. ºÚÁÏÍø researchers found that the administrative prevalence increased in 15 of those 17 school districts, with only the Esmeralda School District-which enrolls fewer than 80 students-reporting no prevalence during the study period.
John Tuman, ºÚÁÏÍø political science professor and lead investigator of the project, says that although his research shows autism prevalence has increased significantly, funding for autism and ASD has not. In fact, for fiscal year 2007-08, the federal funding for all special education programs in Nevada has been cut.
Tuman hopes his research will not only provide greater understanding about ASD disorders but also help correct the discrepancy between the increasing prevalence and public policy.
"By investing in the education of these children on the front end, we can mitigate the barriers to their learning and vastly improve their future and potential for being self reliant," said Tuman. "Successfully doing so would ultimately translate into an enormous cost savings to society, particularly because this population would be much less likely to require government assistance in the future."
Tuman says the research also challenges other recent studies that assert trends in administrative prevalence nationwide are a result of diagnostic substitution-a theory that claims children who were previously classified as having mental retardation or speech/language difficulties are now being reclassified as autistic.
"Our research shows no evidence whatsoever to suggest that diagnostic substitution is driving the increase in autism prevalence in Nevada," said Tuman. "If diagnostic substitution had been a factor, the study would have shown a corresponding decrease in the reporting of other learning disabilities. But some of those are also on the rise."
According to Sheniz Moonie, assistant professor, epidemiologist and biostatistician in ºÚÁÏÍø's School of Public Health, assessing true increases in administrative prevalence of autism involves accurate measurement, including sophisticated biostatistical techniques. These techniques help quantify and explain the extent of the burden among the population.
As co-investigator on the project, Moonie applied several statistical models from a public health approach to prevent biases in assessing trends in prevalence over time. Using a conservative quantitative approach, the research still yielded a significant increase in administrative prevalence during the defined assessment period.
Other co-investigators on the project include Danielle Roth-Johnson, visiting assistant professor in the Department of Women's Studies.
The results of the research will be presented May 9 during a free public lecture from 5:30 to 7:30 p.m. in Room 218 of the ºÚÁÏÍø Carlson Education Building. The lecture is being sponsored by the ºÚÁÏÍø Center for Autism Spectrum Disorders.
