Why Youngsters With Autistic Spectrum Disorders Remain Underrepresented in Special Education

By Safran, Stephen P

Although numerous investigations have examined the prevalence of autistic spectrum disorders (ASD) in the general population, have special education identification rates of autism kept pace? From the 1992-1993 to 2001-2002 school years, U.S. Department of Education data indicate an increase from 15,580 to 97,904 students with autism, an expansion of 528% and an annual average growth of 22.69%. The number of students with autism per 10,000 public school enrollees has correspondingly increased from 3.64 to 20.53 during this period. Despite this expansion, there remains a substantial gap between students identified with autism under the Individuals With Disabilities Education Act and current prevalence estimates of ASD, in large part due to underidentification of youngsters on the higher functioning end of the spectrum. Keywords: autism; autistic spectrum disorders; identification; special education

In recent years, there has been a dramatic increase in the number of individuals clinically or medically diagnosed with autism and related conditions, often referred to as autistic spectrum disorders (ASD) or pervasive developmental disorders (PDD; Charman, 2002; Fombonne, 2003b). Although explanations of this estimated threefold to fourfold increase over the past 30 years (Fombonne, 2003b) are preliminary, changes in diagnostic criteria; heightened awareness among the public, parents, and professionals; recognition that ASD can be dual-diagnosed with other conditions; as well as enhanced service access are often cited (Wing & Potter, 2002). Whereas numerous studies investigate the prevalence of ASD in the general population (Croen, Grether, Hoogstrate, & Selvin, 2002; Fombonne, 2003a), there has been scant attention concerning the number of students with autism declared eligible for special education services (Sturmey & James, 2001). (In this article, ASD or PDD is used as the broader medical/clinical term, whereas autism refers to the disability category under the Individuals With Disabilities Education Act [IDEA].) Furthermore, whereas the prevalence rate of ASD in the general population has been dramatically expanding, have identification rates kept pace in the public schools?

Yahoo! Autos

To address this issue, this article examines trends in the number of students identified with autism since the U.S. Department of Education first required states to report these data for school year 1992-1993. What has been the rate of increase in the number of students identified? How do current prevalence estimates of ASD in the general population compare with special education classification rates of autism? To what extent are pupils with ASD potentially being underidentified for special education services under the category of autism?

Contrasting Clinical Diagnosis and Special Educational Identification

The initial step in identifying any clinical or special education population involves defining the disorder or disability. The concept of autism has undergone a significant transformation since Kanner's seminal 1943 paper (Tidmarsh & Volkmar, 2003). Earlier considered a rare condition almost exclusively associated with mental retardation, research during the late 1980s and the 1990s modified this view (Wing & Potter, 2002). Within the clinical and research communities, as the notion of a "spectrum" of autistic disorders became more accepted, studies on the prevalence of ASD began to generate substantially larger numbers (Tidmarsh & Volkmar, 2003; Wing & Potter, 2002).

The educational definition of autism under IDEA (Individuals With Disabilities Act Regulations, 1999) has both similarities and differences when compared with the Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition, Text Revision (DSM-IV-TR; American Psychiatric Association, 2000):

Autism means a developmental disability significantly affecting verbal and nonverbal communication and social interaction, generally evident before age 3, that adversely affects a child's educational performance. Other characteristics often associated with autism are in repetitive activities and stereotyped movements, resistance to environmental change or change in daily routines, and unusual responses to sensory experiences. The term does not apply if a child's educational performance is adversely affected primarily because the child has an emotional disturbance, as defined by IDEA criterion. A child who manifests the characteristics of "autism" after age three could be diagnosed as having "autism" if the criteria in the preceding paragraph are met. (Individuals With Disabilities Act Regulations, 1999)

In contrasting the educational and clinical definitions, Dahl (2003) emphasized that both include deficits in social interaction, in addition to verbal and nonverbal communication. The IDEA definition, however, requires that these characteristics must have a negative impact on educational performance. Moreover, whereas onset can be expected by age 3, this does not preclude diagnosis or development of autistic tendencies at a later age. For example, research hi the United Kingdom indicates that children with Asperger syndrome are on the average identified at a later age (11.13) compared with youngsters with autistic disorder (5.49; Howlin & Asgharian, 1999). Therefore, youngsters on the higher functioning end of the spectrum, whose symptoms often are masked during early childhood (Safran, 2005), can be identified for special education services at an older age under the category of autism.

Protect your Identity with LifeLock!

The clinician and special educator do not use the same diagnostic or identification criteria (Dahl, 2003). Overall, the IDEA definition of autism is considered broad and flexible enough to include students who exhibit a range of behaviors that are included within all ASD subtypes (Fogt, Miller, & Zirkel, 2003; Shriver, Alien, & Mathews, 1999). However, many individuals may not receive both an educational and clinical diagnosis. For instance, a student can be found eligible for special education services without a clinical diagnosis of any ASD subtype, or a clinically diagnosed youngster may not receive special education services. Furthermore, a child with a clinical diagnosis of any ASD condition can be identified under other special education categories, often mental retardation or other health impaired (Dahl, 2003). However, the actual number of children with ASD receiving special education services under all categories, including autism, has yet to be systematically examined (see YearginAllsopp et al. [2003] and Bertrand et al. [2001] for preliminary data). Furthermore, although the frequency of IDEA due process hearings and legal decisions encompassing autism have increased, only 13 of the 290 (4.5%) identified by Fogt et al. (2003) involved differences over eligibility. This evidence suggests that the educational definition of autism is operationally acceptable to both the legal and advocacy communities.

Prevalence Estimates of Autistic Spectrum Disorders

What is the prevalence of children with ASD? Whereas this appears to be a straightforward question, an accurate answer challenges researchers and epidemiologists throughout the world (Baker, 2002; Chakrabati & Fombonne, 2001; Scott, Baron-Cohen, Bolton, & Brayne, 2002). Differences in prevalence estimates across studies can result from methodological variability, including differences in definition, geographic area, and/or strategies used to identify/ diagnose individuals (Fombonne, 2003a). In the United States there have been three widely cited studies of the prevalence of ASD: the California Developmental Services investigation (California Department of Developmental Disabilities, 1999; Croen, Grether, Hoogstrate, et al., 2002; Croen, Grether, & Selvin, 2002); the Centers for Disease Control and Prevention's (CDC's) Atlanta, Georgia, examination (Yeargin-Allsopp et al., 2003), and the CDC's Brick Township, New Jersey, inquiry (Bertrand et al., 2001). Each of these investigations, however, used widely varying methodological approaches, and the accuracy of their results has been questioned (Fombonne, 2003a, 2003b).

Arguably the most current and accurate prevalence estimates of combined ASDs can be derived from Fombonne's (2003a) review of epideniiological studies. Analyzing international research, he suggested a conservative estimate of 27.5 per 10,000 but supported a more realistic number of 60.0 per 10,000, a figure corroborated by Charman (2002). Based on U.S. census data from 2000, and his conservative estimate, Fombonne (2003a) presented his approximation for the number of individuals under 20 with all subtypes of ASD. To expand on his figures, I also include in Table 1 his higher rate of 60.0 per 10,000. According to these estimates, there are between 221,301 and 482,840 individuals with all types of ASD under the age of 20 based on year 2000 census data.

Join the Gallery

Examining Special Education Identification Trends

To what degree are youngsters with ASD potentially underrepresented in special education under the category of autism compared with current prevalence estimates? To address this question, my first step was to identify trends related to the number of students identified with autism under IDEA. These data are based on annual reports of the implementation of the Individuals With Disabilities Education Improvement Act (previously IDEA and PL 94- 142), beginning with the 1991-1992 school year (U.S. Department of Education, 1992) until the most recently released head counts for the 2001-2002 school year (U.S. Department of Education, 2002). Statistics were collected using electronic versions of these reports starting in 1995, with earlier hardcopy editions utilized between 1992 (U.S. Department of Education, 1992) and 1994. By law, all states are required to yearly submit the number of students identified by special education category. Although autism identification rates were first collected in 1991-1992, required reporting by the states began in 1992-1993 (U.S. Department of Education, 2002). As a result, only figures starting from 1992-1993 are reported. In addition, the most recent report available (U.S. Department of Education, 2002) also incorporates retrospective identification data derived from previous editions. In instances where a discrepancy exists between earlier reported figures and those most recently released, more recent numbers are included. Enrollment statistics pertaining to the entire public school population were retrieved from Department of Education online sources rounded to the nearest thousand (National Center for Education Statistics, 2004). * How many students have been identified under the category of autism under IDEA for each school year between 1992-1993 and 2001-2002? What has been the annual rate of increase?

The number of students ages 3 to 22 identified with autism reported by the federal government has increased from 15,580 in 1992- 1993 to 97,904 in 2001-2002, an increase of some 528% (see Figure 1). Annual increases from 1993-1994 to 2001-2002 varied from a low of 18.22% in 1996-1997 to a high of 27.15% in 1995-1996, with an average annual increase of 22.69% (see Figure 2).

* What percentage of all students with disabilities under IDEA have been identified with autism between 1992-1993 and 2001-2002?

To analyze the growth of the number of students with autism relative to all pupils with disabilities, percentages were calculated. As illustrated in Figure 3, this number has grown each successive year, from a low of 0.34% in 1992-1993 to a high of 1.66% in 2001-2002.

* What has been the rate of students identified with autism per 10,000 students enrolled in public schools between 1992-1993 and 2001-2002? How does this compare with current prevalence estimates of ASD in the general population?

To make a more meaningful comparison between children identified with autism in the public schools and prevalence estimates derived from epidemiological studies, the number of students with autism was compared with total national public school enrollment. The number of students varied from a low of 3.64 per 10,000 in 1992-1993 to a high of 20.53 in 2001-2002 (see Figure 4). This latter figure, though representing a substantial growth rate, remains approximately 6.97 per 10,000 below Fombonne's (2003a) conservative estimate of 27.5 per 10,000, or approximately 33,227 students based on a total public school enrollment of 47,672,000 for Fall 2001 (National Center for Education Statistics, 2004) . Furthermore, the IDEA figures are approximately 39.47 per 10,000 below his more realistic number of 60.0 per 10,000, or an estimated 188,161 students.

* What were the number of students identified with autism at each age between 3 and 22 during the most recent school year?

As illustrated in Figure 5, the largest number of students identified with autism under IDEA per age group are 9-year-olds (n = 11,641), followed by ages 8 (n = 11,379) and 7 (n = 11,121). As can be perused from these numbers, there appears to be a "plateau" from ages 6 to 9, followed by a consistent decrease starting at age 10.

Why Youngsters With Autism Remain Underidentified in Special Education

Whereas prevalence estimates of individuals with ASD has dramatically expanded (Charman, 2002; Fombonne, 2003a), has the number of students identified with autism under IDEA kept pace? On the surface, comparing 1992-1993 to 2001-2002 data from the U.S. Department of Education (1992, 2002) reflect several noteworthy accomplishments: a 528% increase in the number of students identified (from 15,580 to 97,904), an expansion in the student classification rate (from 3.64 to 20.53 per 10,000 public school pupils), plus an average annual growth rate of 22.69%. Despite these extensive efforts, it is my view that youngsters with ASD remain underrepresented in special education.

Whereas estimating special education identification rates is a haphazard business, whole population prevalence estimates can provide insights into future classification needs. If the number of students identified with autism is equivalent to current ASD prevalence estimates, somewhere between 27.5 and 60.0 per 10,000 (Bertrand et al., 2001; Fombonne, 2003a), and we combine this with a Fall 2001 public school enrollment of 47,672,000 (National Center for Education Statistics, 2004), the number of students with autism can be projected at between 131,098 and 286,032, or a required increase of between 34% to 192% from the 2001-2002 identification count of 97,904. If, and this is a big if, prevalence estimates of ASD can serve as a general guide for future growth, there potentially remain tens of thousands of public school students yet to be identified with autism according to the most recent federal figures available at time of writing. If a near-term annual growth rate of 20% is maintained, plus applying Fombonne's (2003a) best estimate of 60.0 per 10,000 individuals (286,032 students with autism), this identification rate would be reached during the 2007- 2008 school year. Realistically, a 20%-plus annual growth rate cannot be sustained indefinitely as funding pressures spiral due to budget restraints.

Try AeroGarden for only $19.95

Whereas I believe that there is a strong case for identifying greater numbers of students with autism, this position is arguable for several reasons. First, although actual figures are unknown, many children with ASD are identified in other special education disability categories such as mental retardation or other health impaired (Bertrand et al., 2001; Yeargin-Allsopp et al., 2003), thereby reducing the number classified with autism. second, prevalence estimates derived from epidemiological research are just that, estimates of population size. These figures differ from "administrative" head counts such as special education identification numbers where funding may be the dominant factor in determining population size. Third, the diagnostic criteria for all subtypes of ASD and the special education definition of autism, though overlapping, differ and will invariably result in different eligibility and diagnostic decisions.

Cigarrest to Stop Smoking in 7 Days!

Where on the autistic spectrum can future increases in identification be projected to emanate from? Although exact numbers are currently unavailable, it is probable that professionals in early intervention and special education have already identified the vast majority of children on the lower end of the spectrum. These youngsters are diagnosed at an earlier age, and their symptoms are more visible to families and professionals (Howlin & Asgharian, 1999). As investigations in the United States corroborate (Bertrand et al., 2001 ; Yeargin-Allsopp et al., 2003), higher functioning youngsters with ASD, such as those diagnosed with Asperger syndrome, whose symptoms are often more subtle and may be masked due to average to above-average intellectual functioning, academic achievement, and language abilities, are either identified at an later age or not at all (Howlin & Asgharian, 1999; Safran, 2005). Although progress has been made, there remain many more youngsters on the higher end who remain unidentified. For these youngsters, whose social skills deficits, unusual mannerisms, rigidity, and lack of empathy are often wrongfully interpreted as purposefully rude and inappropriate, life challenges are no less real (Safran, 2001). It is with this group of children that future special education identification resources must be focused.


American Psychiatric Association. (2000). Diagnostic and statistical manual of mental disorders (4th ed., text revision). Washington, DC: Author.

Baker, H. C. (2002). A comparison of autistic spectrum disorder referrals 1997 and 1989. Journal of Autism and Developmental Disorders, 32, 121-125.

Bertrand, J., Mars, A., Boyle, C., Bove, F, Yeargin-Allsopp, M., & Decloufe, P. (2001). Prevalence of autism in a United States population: The Brick Township New Jersey, investigation. Pediatrics, 108, 1155-1161.

California Department of Developmental Disabilities. (1999). Changes in the population of persons with autism and pervasive developmental disorders in California's Developmental Services System: 1987 though 1999. A report to the legislature. Sacramento: California Health and Human Services Agency.

Chakrabati, S., & Fombonne, E. (2001). Pervasive developmental disorders in preschool children. Journal of the American Medical Association, 285, 3093-3099.

Charman, T. (2002). The prevalence of autism spectrum disorders: Recent evidence and future challenges. European Child & Adolescent Psychiatry, 11, 249-256.

Croen, L. A., Grether, J. K., Hoogstrate, J., & Selvin, S. (2002). The changing prevalence of autism in California. Journal of Autism & Developmental Disorders, 32, 207-215.

Croen, Lisa A., Grether, J. K., & Selvin, S. (2002). Descriptive epidemiology of autism in a California population: Who is at risk? Journal of Autism & Developmental Disorders, 32, 217-224.

Dahl, K. B. (2003). The clinical and educational systems: Differences and similarities. Focus on Autism and Other Developmental Disabilities, 18, 238-246.

Fogt, J. B., Miller, D. N., & Zirkel, P. A. (2003). Defining autism: Professional best practices and published case law. Journal of School Psychology, 41, 201-216. Fombonne, E. (2003a). Epidemiological surveys of autism and other pervasive developmental disorders: An update. Journal of Autism & Developmental Disorders, 33, 365-382.

Fombonne, E. (2003b). The prevalence of autism. Journal of the American Medical Association, 289, 87-89.

Howlin, P., & Asgharian, A. (1999). The diagnosis of autism and Asperger syndrome: Findings from a survey of 770 families. Developmental Medicine and Child Neurology, 41, 834-839.

Individuals With Disability Act Regulations. 34 C.F.R. 300.7 (1999).

National Center for Education Statistics. (2004). Digest of education statistics, 2004. Washington, DC: U.S. Department of Education. Retrieved September 25, 2006, from http:// www.nces.ed.gov/programs/digest/d04/

Safran, S. P. (2001). Asperger syndrome: The emerging challenge to special education. Exceptional Children, 67, 151-160.

Safran, S. P. (2005). Diagnosis. In L. J. Baker & L. A. Welkowitz (Eds.), Asperger's syndrome: Intervening in schools, clinics, and communities (pp. 43-61). Mahwah, NJ: Lawrence Erlbaum.

Scott, F. J., Baron-Cohen, S., Bolton, P., & Brayne, C. (2002). Brief report: Prevalence of autism spectrum conditions in children aged 5-11 years in Cambridgeshire, UK. Autism, 6, 231-237.

Shriver, M. D., Alien, K. D., & Mathews, J. R. (1999). Effective assessment of the shared and unique characteristics of children with autism. School Psychology Review, 28, 538-558.

Sturmey, P., & James, V. (2001). Administrative prevalence of autism in the Texas school system. Journal of the American Academy of Child & Adolescent Psychiatry, 40, 621.

Tidmarsh, L., & Volkmar, F. R. (2003). Diagnosis and epidemiology of autism spectrum disorders. Canadian Journal of Psychiatry, 48, 517-525.

U.S. Department of Education. (1992). To assure the free appropriate public education of all handicapped children with disabilities: Fourteenth annual report to Congress on the implementation of the Education of All Handicapped Children Act (Public Law 94-142). Washington, DC: Author.

U.S. Department of Education. (2002). To assure the free appropriate public education of all children with disabilities: Twenty-fourth annual report to Congress on the implementation of the Individuals With Disabilities Act (IDEA). Washington, DC: Author. Retrieved September 26,2006, from http://www.ed.gov/about/reports/ annual/otherplanrpts.html

Wing, L., & Potter, P. (2002). The epidemiology of autistic spectrum disorders: Is the prevalence rising? Mental Retardation and Developmental Disabilities Research Review, 8,151-161.

Yeargin-Allsopp, M., Rice, C., Karapurkar, T, Doernberg, N., Boyle, C., & Murphy, C. (2003). Prevalence of autism in a US metropolitan area. Journal of the American Medical Association, 289, 49-55.

Stephen P. Safran

Ohio University, Athens

Author's Note: This research was completed during the author's faculty leave at Ohio University during academic year 2005-2006. Please address correspondence to Stephen Safran, PhD, Ohio University, Dept. of Teacher Education, College of Education, McCracken Hall, Athens, OH 45701; e-mail: safran@ohio.edu.

Stephen P. Safran, PhD, is a professor of special education at Ohio University, Athens. He received his PhD at the University of Virginia in special education. His current research, presentation, and training interests include school-wide positive behavior supports and autistic spectrum disorders/Asperger syndrome.

No comments: