Special Needs in the US
The number of children in each sub-group (intellectual disabilities, Autism Spectrum Disorder, and Down Syndrome) is based on data from the Centers for Disease Control and Prevention (CDC), Department of Education (DOE), and U.S. Census Bureau.
In order to determine what meets the criteria of a special need, the Individuals With Disabilities Education Act (IDEA) is used. The IDEA specifies thirteen conditions, including autism and intellectual disabilities, that qualify a student for special education under an Individualized Education Program (IEP) plan:
4. Emotional Disturbance
5. Hearing Impairment
6. Intellectual Disability
7. Multiple Disabilities
8. Orthopedic Impairment
9. Other Health Impaired
10. Specific Learning Disability
11. Speech or Language Impairment
12. Traumatic Brain Injury
13. Visual Impairment
Using IDEA definitions, any of these thirteen conditions can be considered a special need. In 2017 the number of children age 0-10 in the U.S. with disabilities requiring special education is calculated to be approximately 3,359,615.
SPECIAL NEEDS TOTALS
From 2000-2001, approximately 6,083,000 students (age 3-21) had disabilities requiring special education. That number decreased to 6,054,000 by 2014. That averages to a decrease each year of approximately 2,231 students. Assuming a linear decrease, that gives us a total of 6,047,307 special education students (age 3-21) in 2017.
Assuming the probability of disabilities requiring special education being equally distributed among each age group range by year, the total children age 10 and under with special needs as defined by the IDEA is 3,359,615 ([6,047,307 / 18] x 10).
In 2017, the number of children with intellectual disabilities (not including Down Syndrome and autism) in age 0-10 is calculated to be approximately 210,598. Intellectual disability is defined by the American Association on Intellectual and Developmental Disabilities as "significant limitations in both intellectual functioning and in adaptive behavior."
From 2000-2001, approximately 624,000 people age 3-21 had an intellectual disability. This number decreased to 425,000 by 2014. That averages to a decrease per year of 15,308 students with intellectual disabilities. Assuming a linear decrease per year, the number of students (age 3-21) with intellectual disabilities in 2017 in the U.S. was 379,096. If we assume the probability of intellectual disability rates distributed equally among each age range by year, the total number of children age 0-10 with intellectual disabilities is approximately 210,598.
In 2017 the number of children age 0-10 with Down Syndrome in the U.S. is calculated to be approximately 47,738; the CDC estimates approximately 6,000 babies born in the U.S. every year have Down Syndrome.
Looking at the CDC estimates, in 2008 about 1 out of every 1,200 people (all ages) in the United States had Down Syndrome. With a population in 2008 of 304,093,966, given that 1 in 1200 people had Down Syndrome, the total number of people in the U.S. with Down Syndrome in 2008 was approximately 253,412. Assuming Down Syndrome has an equal probability of occurrence in each age bracket, the number of newborns born with Down Syndrome in 2008 was 3,548.
Assuming an equal rate of growth annually from 2008 to 2017 (from 3,548 to 6,000 births), the average increase per year of babies born with Down Syndrome in the U.S. was 272. Totaling the number of babies born each year in the U.S. with Down Syndrome over a period of ten years, given the increase, the number of children born with Down Syndrome each year breaks down as follows:
2008 : Age group (9 – 10) : 3548
2009 : Age group (9-8) : 3820.4
2010 : Age group (8-7) : 4092.8
2011 : Age group (7-6) : 4365.2
2012 : Age group (6-5) : 4637.6
2013 : Age group (5-4) : 4910
2014 : Age group (4-3) : 5182.4
2015 : Age group (3-2) : 5454.8
2016 : Age group (2-1) : 5727.2
2017 : Age group (0-1) : 5999.6 (approximately 6,000)
Therefore, the total number of children age 0-10 with Down Syndrome can be calculated at approximately 47,738.
In 2017 the number of children age 0-10 in the U.S. with autism is calculated to be approximately 355,941. The CDC estimated in 2012 that about 1 in 68 children at some point receives a diagnosis of Autism Spectrum Disorder. This average does not account for gender disparity in diagnosis, which for boys is 1 in 42, and for girls is 1 in 189. Studies across North America, Europe, and Asia indicate between 1% and 2% of the population on average as having Autism Spectrum Disorder.
From 2000-2001, 93,000 people age 3-21 in the U.S. were diagnosed as having autism, which increased to 538,000 by 2014. Assuming equal distribution in increase per year of autism diagnoses, that is an increase annually of approximately 34,231 autism diagnoses. Assuming the average increase maintains annually, by the end of 2017 the number of autism diagnoses in children age 3-21 totaled approximately 640,693.
If we assume the probability of having autism is equally distributed among each age group, the number of children age 0-10 with autism is calculated at approximately 355,941.