This study aimed to determine the local prevalence of autism spectrum disorder (ASD) in Calgary, Alberta and surrounding areas. The researchers obtained school records from three major school boards and several independent schools in the area, which identified 1,711 children with an ASD diagnosis out of 160,904 total students, equivalent to a prevalence of 1 in 94. Prevalence was higher in elementary grades (1 in 86) compared to junior and senior grades. These local prevalence estimates can help inform policymakers of resources needed for education, employment programs, and housing as these children age.

1. Laying the Foundation for Policy: Measuring Local Prevalence for Autism Spectrum Disorder
Katelyn Lowe, Carolyn Dudley, Daniel J. Dutton, Jennifer D. Zwicker, Carly McMorris, J.C. Herbert Emery, David B Nicholas, Margaret Clarke
 Prevalence information is vital to guide policy makers in resource allocation
 In Canada ASD prevalence is reported in national figures based on international estimates but these
broad estimates may not be an accurate estimate of local prevalence and consequently local needs
 The province of Alberta has provided for a number of years some of the highest levels of funding for
children with ASD across Canada and because of this there is speculation of higher prevalence due to
in-migration for services
 National estimates of ASD may not reflect provincial estimates and local needs and basic local numbers
are needed
 School records in Calgary (a major urban center within the province of Alberta, Canada) and the
surrounding area could provide a feasible method to collect local prevalence
 To determine how many children are living with ASD in Calgary and surrounding areas of several other
smaller municipalities that comprise a total population of approximately 1.2 million people.
 School records provided by three major school boards and a number of independent and private schools
in Calgary and area were used to count the number of children living with an ASD diagnosis in the
geographical area of Calgary and surrounding communities.
 All children with an ASD diagnosis receive a special education numeric code on their record based on a
diagnosis of ASD which requires proof from a register health professional in Alberta.
 Special education codes are used for students with a disability to assign levels of required support. Codes
are categorized as mild/moderate or severe based on the students functional ability and behaviors.
 Each school board, independent and/or private school reviewed their data base of registered children and
extracted codes or records for children having a diagnosis of ASD.
 Records for all children in the specified geographical area from Grade 1 to Grade 12 who attended in the
2012-2013 school year were placed into a data set and records of those with an ASD diagnosis were ex-
tracted.
It is critical for policy makers to know local prevalence so that they can be aware of the extent of the
situation in their own jurisdictions and develop the supports needed
1 in 94 school age children have an ASD diagnosis in Calgary and surrounding area
Prevalence is higher in elementary-grade children where 1 in 86 had an ASD diagnosis
Reasons for the increased prevalence in lower grades are unknown but could be related to an increased
drop-out rate in higher grades, higher numbers moving to homeschooling and/or a true rise in
prevalence
The prevalence was similar to national estimates which suggests in-migration to Alberta for funding has
not had a significant impact on prevalence
These prevalence estimates help inform the policy makers on numbers in need of special education
services and for future planning needs as adolescents move into adult services at age 18
BACKGROUND SIGNIFICANCE
OBJECTIVES
METHOD
RESULTS
The prevalence of ASD for all children across all grades was 1 in 94 while the reported prevalence from the
CDC (2014) was 1 in 68. Taking only elementary grades the prevalence was 1 in 86. The surprising finding
was that a significant difference existed between the senior grades and lower grades. The decreased
numbers of children with ASD in senior grades was specific to one school board. It is possible that students
are dropping out in senior grades or moving into homeschooled settings. The difference could also be a
result of improved screening in younger grades, changing diagnostic criteria, general increased ASD
awareness or a true rise in prevalence.
DISCUSSION
CONCLUSION
 Prevalence estimation is important to guide policy makers in resource allocation. With rapidly rising
prevalence rates there is urgency to understand prevalence estimates for government discussions.
Prevalence estimates are often presented based on national estimates but these may not reflect local
numbers and needs.
 This study provides the first local-prevalence estimates for ASD in Alberta. Knowing that 1 in 94
children are living with ASD and that the numbers are increasing will help policy makers manage school
resources, employment programs and future housing needs.
 This study demonstrates a successful process of effectively working within and across school boards to
access records of children living with ASD and offers an alternate approach to estimate regional
prevalence.
STUDY LIMITATIONS
1.Not all independent schools participated and it was not possible to count the number of homeschooled
children in the area. We estimate that we captured approximately 91% of all children attending school in
the area.
2. The ASD diagnosis on record was obtained by a qualified health professional but there was no standard
diagnostic review across boards and schools to confirm the diagnosis.
3. This review used only one source of records (school records) as opposed to a more comprehensive
multiple record review that would include school and health records.
We gratefully acknowledge the support of all participating school boards and independent or private
schools in this project.
School Boards
CBE CCSD Rocky View Other Total
Total number of children enrolled 97,293 44,774 16,868 1,969 160,904
Autistic Disorder 570 223 72 132 997
Asperger's Disorder 209 79 36 20 344
Other 225 84 32 29 370
Total Diagnosed 1,004 386 140 181 1,711
Table 1: 1 in 94 children across all schools have a diagnosis of ASD
School Boards
CBE CCSD Rocky View Other Total
Male 859 325 108 142 1434
Female 145 61 32 39 277
Ratio M:F 5.9:1 5.3:1 3.4:1 3.6:1 5.2:1
Table 2: ASD diagnosis by sex across boards shows the male to female ratio is 5.2:1
Diagnostic Category Total number Percent
Autistic Disorder 997 58.27%
Asperger's Disorder 344 20.11%
Other 370 21.62%
Total 1711 100.00%
Table 3: Total count in all schools by diagnostic category
Grade Level Prevalence per 1,000 Cases Ratio
Elementary 11.61* 1 in 86
Junior 11.11* 1 in 90
Senior 8.88 1 in 113
* Indicates statistically different from Senior prevalence at 5%
significance
Table 4: Prevalence of an ASD by School Category