Number 87 n November 13, 2015

Estimated Prevalence of Autism and Other
 

Developmental Disabilities Following Questionnaire
 

Changes in the 2014 National Health Interview Survey
 by Benjamin Zablotsky, Ph.D. and Lindsey I. Black, M.P.H., National Center for Health Statistics;
 

Matthew J. Maenner, Ph.D. and Laura A. Schieve, Ph.D., National Center on Birth Defects and Developmental
 

Disabilities; and Stephen J. Blumberg, Ph.D., National Center for Health Statistics
 

Abstract

Objectives—The developmental disabilities questions in the 2014 National

Health Interview Survey (NHIS) were changed from previous years, including

question reordering and a new approach to asking about autism spectrum

disorder (ASD). This report examines survey-based estimates of the lifetime

prevalence of ASD, intellectual disability (ID), and any other developmental

delay (other DD) following the inclusion of a standalone ASD question, the

inclusion of specific diagnoses in the ASD question, and the ASD question

preceding the other DD question, and compares them with estimates from

previous years.

Methods—In NHIS, one child is randomly selected from each family to be

the subject of detailed questions on health conditions, functional limitations, and

health care utilization. Parents are asked if a doctor or health professional had

ever told them that their child had each of a series of developmental disabilities.

Prevalence estimates of ASD, ID, and other DD for children aged 3–17 years

were calculated using data collected in 2011–2014.

Results—The estimated prevalence of ASD based on 2014 data was 2.24%, a

significant increase from the estimated annualized prevalence of 1.25% based on

2011–2013 data. In contrast, the prevalence of other DD declined significantly

from 4.84% based on 2011–2013 data to 3.57% based on 2014 data. The

prevalence of ID did not significantly change from 2011–2013 (1.27%) to 2014

(1.10%). The prevalence of having any of the three conditions was constant

across survey years.

Conclusions—The revised question ordering and new approach to asking

about developmental disabilities in the 2014 NHIS likely affected the prevalence

estimates of these conditions. In previous years, it is likely that some parents of

children diagnosed with ASD reported this developmental disability as other DD

instead of, or in addition to, ASD. Following these changes, the 2014 ASD

estimate was more similar to ASD prevalence estimates from other sources.

Keywords: autism spectrum disorder • developmental disabilities • national

survey • children

Introduction

Developmental disabilities are

heterogeneous and lifelong disorders

that are often characterized by problems

related to the functioning of the brain or

senses and include genetic disorders that

affect cognition, behavior, and multiple

body systems. Children diagnosed with

developmental disabilities typically

require a substantial number of services

and treatments to address both

behavioral and developmental

challenges (1). Measuring the prevalence

of these conditions in children aids in

assessing the adequacy of available

services and interventions that may

improve long-term outcomes.

Challenges to estimating the

prevalence of developmental disabilities

include changing definitions and

labeling practices over time, as well as

the high probability of co-occurring

conditions that fall under the umbrella

term of developmental disabilities. It is

difficult to interpret trends in prevalence

over time because of the possibility of

‘‘diagnostic substitution,’’ whereby

labeling practices might change and

cause similar symptoms to be classified

under different disabilities during

different time periods. Evidence of this

phenomenon has been shown previously,

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES 

Centers for Disease Control and Prevention 

National Center for Health Statistics 

National Health Statistics Reports 
Page 2 National Health Statistics Reports n Number 87 n November 13, 2015

particularly as it relates to children

receiving special education services (2–

4). For this reason, it can be worthwhile

to simultaneously consider the

prevalence of the individual disorders

that are considered developmental

disabilities as well as the prevalence of

any developmental disabilities as a

whole (5).

Additional challenges stem from the

available methods for estimating

prevalence. Survey-based estimation

relies on respondents understanding the

questions asked, remembering that the

diagnosis was given, recalling that

diagnosis when asked, and accurately

reporting that diagnosis within the

survey context (6,7). Estimates based on

administrative classifications (such as

special education classifications, autism

service eligibility, or medical billing

codes) have other limitations. Certain

segments of the population may have

reduced access to the systems that

generate the administrative counts,

leading to undercounts and specious

socioeconomic disparities in the

prevalence of autism spectrum disorder

(ASD) (8). In addition, the criteria for

special education or other autism-related

services differ from state to state, and

their use is unevenly adopted within

states (9,10). Because each source of

information has different advantages and

limitations, multiple and complementary

systems are needed to best understand

observed changes in the prevalence of

developmental disabilities.

Since 1997, the National Health

Interview Survey (NHIS) has included

questions to determine the prevalence of

children ever diagnosed with the

developmental disabilities of ASD,

intellectual disability (ID), and any other

developmental delay (other DD). In

2014, NHIS revised its approach to

asking about ASD. The question

wording was expanded to include more

specific details on what constituted an

ASD and to align with another national

survey, the 2011–2012 National Survey

of Children’s Health (NSCH).

Additionally in 2014, the ASD question

was included in the survey as a

standalone question that was verbally

asked before the question on other DD,

and after the question on ID (Figure 1).

Before this, the ASD question was

included in a checklist of 10 conditions

provided to the parent; the parent was

asked to read the list and select any of

the 10 conditions that a doctor or health

professional had ever said their child

had. This checklist was provided after

both the ID and other DD questions had

been asked.

Order and contextual changes to a

survey question can influence

respondents’ interpretation of the

questions and the responses they

provide (7). This can result in changes

to the data captured and the resulting

estimates (11). The primary objective of

this report is to evaluate whether the

changes to the NHIS questions on

developmental disabilities in 2014

affected the estimates of lifetime

prevalence of developmental disabilities

in the United States.

Methods

Data source

NHIS data for 2011–2014 were

used for this analysis. NHIS is a

nationally representative household

survey conducted by the Centers for

Disease Control and Prevention’s (CDC)

National Center for Health Statistics.

This cross-sectional survey collects data

continuously throughout the year, and

annual data files permit estimates for the

civilian noninstitutionalized population.

Interviews are conducted in person in

respondents’ homes, with telephone

follow-up if needed. Demographic and

basic health information for all family

members is collected from one or more

adults in the family responding on

behalf of the family. In addition, from

each family, one adult (the sample adult)

and one child (the sample child) are

randomly selected to be the subject of

more detailed health questions. Sample

adults respond for themselves. For the

sample child, a knowledgeable adult

(usually the parent) responds on the

child’s behalf. Further information and a

detailed description of the NHIS sample

design and questionnaire is available

from: http://www.cdc.gov/nchs/nhis.htm.

Data from sample children used for

analysis were restricted to children aged

3–17 years, because many

developmental disabilities are not

recognized by parents or diagnosed by

doctors or health professionals before 3

years of age, particularly ASD (12).

From 2011 through 2014, the annual

number of interviews completed for

sample children aged 3–17 years in

NHIS was 10,554 in 2011; 10,954 in

2012; 10,684 in 2013; and 11,091 in

2014. Combined, interviews totaled

43,283 (2011–2014). The final sample

child response rate ranged from 69.0%

to 74.6% from 2011 through 2013, and

was 66.6% in 2014.

Measures

Intellectual disability

Since 1997, a question on lifetime

ID diagnoses has been included in the

sample child component for children of

all ages; it has always been the first

question asked among a series of

questions on developmental disabilities.

The wording of the ID question was

revised for 2011 to comply with Rosa’s

Law (Pub. L. 111–256), and has

remained consistent from 2011 through

2014. Parents were asked: ‘‘Did a doctor

or health professional ever tell you that

[child’s name] had an intellectual

disability, also known as mental

retardation?’’

Autism spectrum disorder

From 1997 through 2010, sample

children with autism were identified as

part of a 10-condition checklist.

Respondents were asked to read the list,

report whether a doctor or other health

professional had ever told them that the

child had any of the conditions, and if

so, identify which conditions were

diagnosed. The respondent was not

specifically asked about each condition.

From 2011 through 2013, autism

continued to be identified as part of the

same 10-condition checklist, but the

previous wording used to name the

condition (‘‘autism’’) was modified to

‘‘autism/autism spectrum disorder.’’ In

2014, the ASD survey item became a

standalone question; respondents for

sample children aged 2–17 years were

directly asked the question. Futhermore,
National Health Statistics Reports n Number 87 n November 13, 2015 Page 3

 

 

 

 

 

 

 

 

 

 

NOTE: In 2014, following the other developmental delay question, respondents were handed a notecard that contained the remaining nine conditions asked about in 2013. 

SOURCE: CDC/NCHS, National Health Interview Survey, 2011–2013 and 2014. 

Figure 1. Developmental disability questions in the National Health Interview Survey, 2011–2013 and 2014

the question wording was again revised

to specifically name the conditions

included in the Diagnostic and

Statistical Manual of Mental Disorders,

Fourth Edition, Text Revision (DSM-IVTR) definition of ASDs (13), and to

align the question with those found in

other national surveys, namely the

2011–2012 NSCH. Parents were asked:

‘‘Did a doctor or health professional

ever tell you that [child’s name] had

autism, Asperger’s disorder, pervasive

developmental disorder, or autism

spectrum disorder?’’

Other developmental delay

Other DD was ascertained using the

question, ‘‘Has a doctor or health

professional ever told you that [child’s

name] had any other developmental

delay?’’ and was asked of parents of

children of all ages. Although this

question wording has remained

consistent from 1997 through 2014, its

context changed in 2014. In 2014, the

other DD question was asked after the

new standalone question on autism.

Before 2014, the other DD question was

asked before the 10-condition checklist

that included autism, and directly after

the question on intellectual disability.

Figure 1 details the ordering and

wording of the developmental

disabilities questions from 2011 through

2014. The ID question has always come

before the other DD question.

Sociodemographic characteristics

To determine if the questionnaire

changes captured different populations

with different characteristics, the

sociodemographic characteristics of the

population of children diagnosed with

developmental disabilities based on

2014 data were compared with the

sociodemographic characteristics of the

population of children diagnosed with

developmental disabilities based on

2011–2013 data. Sociodemographic

characteristics presented in this report

include: age, sex, race and ethnicity,

health insurance coverage type, family

structure, poverty status, parent’s

education, metropolitan statistical area

(MSA) location of residence, and
Page 4 National Health Statistics Reports n Number 87 n November 13, 2015

geographic region. All sociodemographic

characteristics were based on data

collected from the family respondent. For

more information on the definitions used

for sociodemographic characteristics, see

Technical Notes.

Clinical characteristics

Estimates of selected developmental

conditions other than ASD, ID, and

other DD were also examined. These

include parent-reported lifetime

diagnoses of attention-deficit/

hyperactivity disorder (ADHD) and

learning disability (parents were asked if

they had ever been told that their child

had the condition); stuttering in the past

12 months; and seizures that occurred in

the past 12 months. Additionally,

estimates of current functional

limitations were examined, including

trouble with hearing or vision, walking,

or remembering, and whether the child

needed help with personal care or had

any impairment noted due to a physical,

mental, or emotional problem. Lastly,

receipt of selected services was

examined, including ever receiving

special education or early intervention

services or receiving home care from a

health professional in the past

12 months. For more information on the

clinical characteristics items, see

Technical Notes.

Statistical analysis

For each of the conditions of

interest—ASD, ID, and other

DD—lifetime prevalence (henceforth

referred to as prevalence) of any

parent-reported diagnosis was calculated.

All estimates were weighted to be

representative of the U.S.

noninstitutionalized population of

children aged 3–17 years. Data

weighting procedures are described in

more detail elsewhere (14); the sample

child weight was used for these

analyses. Linear regression was used to

assess the trend over time. Bivariate

logistic regressions were used to assess

changes between the 2011–2013 NHIS

and the 2014 NHIS in the compositions

of the estimated populations of children

diagnosed with the conditions of

interest. Comparisons of estimates are

based on two-tailed significance tests at

the 0.05 level. Weighted point estimates

and variances were calculated in

SUDAAN (15) to account for the

complex sample design.

Results

Prevalence of children ever

diagnosed with

developmental disabilities

The estimated ASD prevalence was

2.24% (1 in 45) in 2014, while

averaging 1.25% (1 in 80) from 2011

through 2013—a significant increase

(p < 0.001) (Figure 2). The estimated

prevalence of other DD was 3.57% in

2014, while averaging 4.84% from 2011

through 2013—a significant decrease

(p < 0.001). The estimated ID prevalence

did not change significantly between

2011–2013 (1.27%) and 2014 (1.10%).

Despite changes to the prevalence

of ASD and other DD, the overall

prevalence of children with either ASD

or other DD did not change between

2011–2013 (5.26%) and 2014 (5.30%).

Similarly, the prevalence of children

with any of the three conditions (ID,

ASD, or other DD) in 2011–2013

(5.75%) and 2014 (5.76%) did not differ

significantly.

Characteristics of children

with ASD

Although an increase was observed

in the estimated prevalence of children

diagnosed with ASD (based on parent

report), the sociodemographic

characteristics of the estimated

populations of children ever diagnosed

with ASD remained generally the same

before and after the survey change

(Tables 1 and 2). Children with ASD

were mostly male (81.7% in 2011–2013,

75.0% in 2014) and non-Hispanic white

(58.9% in 2011–2013, 59.9% in 2014),

living in families in large MSAs (58.0%

in 2011–2013, 54.7% in 2014), with two

parents (65.9% in 2011–2013, 68.0% in

2014), and with at least one parent who

had more than a high school level of

education (76.0% in 2011–2013, 67.6%

in 2014). None of these differences were

statistically significant between years.

Estimates based on the 2014 data

show that 22.9% of children ever

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 2. Estimated lifetime prevalence of children aged 3–17 years with parent-reported

developmental disability, by survey year: United States, 2011–2013 and 2014
National Health Statistics Reports n Number 87 n November 13, 2015 Page 5

diagnosed with ASD were also said to

have been diagnosed with other DD, a

significant decrease from 66.7% based

on 2011–2013 data (p < 0.001).

However, for the estimated population

of children ever diagnosed with ASD

using the 2014 data, the likelihood of

having been diagnosed with ADHD, ID,

or a learning disability was not

significantly different from the

likelihood based on the 2011–2013 data.

Children ever diagnosed with ASD

using the 2014 data were also equally

likely to have physical limitations and to

be receiving special education or early

intervention services or home care when

compared with children with ASD using

the 2011–2013 data.

Characteristics of children

with other DD

The demographic characteristics of

children ever diagnosed with other DD

closely resembled those of children ever

diagnosed with ASD (Tables 3 and 4).

Children with other DD were mostly

male, non-Hispanic white, and living in

households with two parents, in large

MSAs, with at least one parent who had

more than a high school level of

education. No differences were found in

the sociodemographic and clinical

characteristics of the populations ever

diagnosed with other DD, whether those

populations were estimated based on

2014 data or 2011–2013 data.

Moreover, no differences in the

sociodemographic and clinical

characteristics of the populations ever

diagnosed with either ASD or other DD

were found, regardless of whether the

population was estimated based on 2014

data or 2011–2013 data (Tables 5 and

6). Likewise, sociodemographic and

clinical characteristics did not differ

between survey years when examining

the populations ever diagnosed with any

of the three conditions (Tables 7 and 8).

Discussion

The 2014 NHIS included a change

to the wording of the ASD question, a

change to the way the ASD question

was asked, and a change in the

placement of the ASD question within

the survey questionnaire. These changes

had the potential to impact the estimated

prevalence of ASD directly while also

having a trickledown effect on the

estimated prevalence of conditions that

were asked about later in the

questionnaire. Indeed, the significant

increase in ASD prevalence and

decrease in other DD prevalence seen

from 2011–2013 to 2014 suggests that

these changes did produce a

measurement effect.

It cannot be ruled out that a true

reduction of other DD diagnoses may

have occurred in the population between

survey years. However, true year-to-year

changes of the magnitude observed are

unusual, and require abrupt or dramatic

changes in the risk factors acting on the

population (16). It also cannot be

concluded that the increase seen in the

prevalence of ASD is completely

explained by the three changes made to

the survey. However, the virtually

identical prevalence estimates of

children ever diagnosed with any

developmental disability in 2011–2013

and 2014 suggests that, before 2014,

some parents of children diagnosed with

ASD reported this developmental

disability as other DD instead of, or in

addition to, ASD.

It would be expected that some

parents of children with ASD answered

yes to their child ever having ‘‘any

other developmental delay’’ in 2011–

2013, given that developmental delays

in social interaction, language, and

imaginative play are prototypical

symptoms of ASD. It is less obvious

why some of these parents did not

report the child’s ASD when the

condition was later presented as part of

the list. It is possible that parents simply

overlooked it, or they may have

assumed that the survey interviewer

would follow conversational norms and,

therefore, would not ask redundant

questions or expect redundant

responses (17). The same principle can

explain why the prevalence of other DD

was lower in 2014. After reporting their

child’s ASD, parents likely assume

(correctly, it is worth noting) that the

next question about other DD is asking

about something other than ASD, and,

therefore, should not be endorsed unless

another non-ASD (and non-ID)

developmental delay was diagnosed.

This explanation suggests that ASD

prevalence estimates based on the 2014

data are more sensitive in capturing the

full population of children with ASD

than estimates based on the 2011–2013

data. When the ASD question is asked

directly and when it comes before the

other DD question, it is likely to receive

more attention and more thoughtful

responses (18). Similar order effects for

questionnaire items on psychological

disability and social disability have been

observed by other researchers (19).

Nonetheless, it is not discernible from

the data available whether the increase

in sensitivity of ASD reporting was at

the expense of decreased specificity.

The 2014 survey brought additional

attention to the ASD question by

including the names of specific

diagnoses within the autism spectrum.

The addition of Asperger’s disorder and

pervasive developmental disorder (PDD)

to the question in 2014 was intended to

help cue recall of past diagnoses and

clarify for parents what conditions were

to be included as autism spectrum

disorders. A similar change to the ASD

question in NSCH between 2003 and

2007 led to higher prevalence estimates

attributed partly to the wording

change (20).

The change in the ordering of

questions and the resulting lower

prevalence of other DD in 2014 suggest

that the other DD question is assessing a

different concept in 2014 than in

2011–2013. Before 2014, it includes

ASD-related delays; in 2014, it is less

likely to include such delays. Analysts

examining trends in developmental

disabilities should therefore use caution

when examining changes over time in

ASD and other DD, but the combined

estimate appears to be stable over time.

Limitations

Caution regarding the 2014

estimates is warranted because of

several survey-related limitations. The

reliance on parent reports could result in

misreporting of children’s diagnoses and

may also be subject to recall biases. For

example, with the addition of PDD to
Page 6 National Health Statistics Reports n Number 87 n November 13, 2015

the ASD question in 2014, some parents

may hear ‘‘developmental disorder’’ but

not hear or understand the word

‘‘pervasive,’’ leading them to incorrectly

report a non-ASD developmental delay

as ASD. Parents’ reports were not

substantiated through clinical evaluation

or educational records. Because parents

are asked to reflect only on the lifetime

prevalence of developmental disabilities

rather than current diagnoses, children

who have lost their original diagnosis

might be included in the reported

prevalence. There are many reasons

children who received a diagnosis in the

past may no longer meet the criteria for

a diagnosis, including, but not limited

to, maturation, misdiagnosis, and

effective treatment (21). Children may

also have lost their original diagnosis

due to changing diagnostic criteria (22).

In addition, NHIS is a survey of the

noninstitutionalized population and,

therefore, children living in places other

than the household (e.g., hospitals)

would not be included in a reported

prevalence. Finally, only 1 year of data

post-survey change are available to be

analyzed; additional years of data will

help improve the precision of the

estimates and allow a better assessment

of trends for developmental disabilities.

Autism spectrum disorders

surveillance

CDC has been tracking the

prevalence of ASD for nearly 20 years.

Besides NHIS, CDC has conducted

NSCH and currently supports the

Autism and Developmental Disabilities

Monitoring (ADDM) Network. Table A

provides a description of each system as

well as the most recent prevalence

estimate of children with ASD. The

three systems use different sampling

strategies, including different age

groups, and they also use different

methods to ascertain ASD. Although

recent data from the most recent NHIS,

NSCH, and ADDM Network reports

contain converging prevalence estimates,

the three systems are not directly

comparable; instead, the findings from

NHIS, NSCH, and ADDM Network

each contribute unique information that,

when combined, helps form a

comprehensive picture of ASD among

children in the United States.

NHIS represents the most in-depth

health survey, with more than 12,000

sample-child interviews completed

annually about health conditions,

functional limitations, and health care

access and utilization. In-person

interviews and strong response rates

make NHIS the principal source of

information on the health of the

noninstitutionalized population of the

United States. As noted earlier, NHIS

has asked about lifetime diagnoses of

autism in children since 1997 (23).

Annual estimates since 1997 for

children aged 3–17 years are presented

in Figure 3. Although the sample size

for NHIS is smaller than the other

systems, the NHIS survey design allows

for multiple years of data to be

combined and analyzed together.

NSCH was conducted in 2003,

2007, and 2011–2012 as a national

telephone survey that focused

exclusively on children; approximately

95,000 interviews were conducted per

cycle. With its large sample size,

in-depth subanalyses—such as

examining sociodemographic

characteristics of children with

autism—are possible with NSCH

(24–26). Like NHIS, NSCH asked

parents if their child had ever been

diagnosed with ASD, but it also asked

parents if the child currently had ASD.

Parents provided extensive information

about their child, including the presence

of co-occurring conditions, ASD

severity, as well as health care

utilization and neighborhood and family

characteristics. The NSCH sample was

designed to be representative of children

in the United States, but declining

response rates over time raised concerns

about increasing bias. Nonresponse bias

cannot be ruled out, although careful

analyses suggested that adjustments to

the sample weights in 2011–2012

reduced the bias to be smaller than the

Table A. Comparison of National Health Interview Survey, Autism and Developmental Disabilities Monitoring Network, and National

Survey of Children’s Health

Characteristics National Health Interview Survey

Autism and Developmental

Disabilities Monitoring Network National Survey of Children’s Health

Year of most recent publication ....... 2015 2014 2013

Year of most recent data set......... 2014 2010 2011–2012

ASD prevalence estimate........... 22.4 per 1,000 children 14.7 per 1,000 children 20.0 per 1,000 children

Age of target population ........... 3–17 years 8-year-olds 6–17 years

ASD ascertainment method ......... Parent-reported survey responses

about a lifetime autism spectrum

disorder diagnosis

Expert clinicians review medical and

education records and apply

surveillance case definition

Parent-reported survey responses

about current autism spectrum

disorder diagnosis

Catchment area or target population .... In a national in-person household

survey of the civilian

noninstitutionalized population

In 14 communities across the

United States (parts of AL, AZ, AR,

CO, FL, GA, MD, MO, NJ, NC, PA,

SC, UT, and WI)

In a national telephone survey of

households with children

Survey sample size .............. Approximately 13,000 Approximately 360,000 Approximately 95,000

Conducted by .................. NCHS NCBDDD NCHS

Primary funder ................. CDC CDC HRSA

Most recent previous data set ........ 2013 (published in 2014) 2008 (published in 2012) 2007 (published in 2009)

NOTES: ASD is autism spectrum disorder. NCHS is National Center for Health Statistics; NCBDDD is National Center on Birth Defects and Developmental Disabilities; CDC is Centers for Disease

Control and Prevention; and HRSA is Health Resources and Services Administration.
National Health Statistics Reports n Number 87 n November 13, 2015 Page 7 NOTES: Dashed lines indicate changes in the approach to asking about autism. During 1997–2010, children with autism were identified as part of a 10-condition checklist. 

During 2011–2013, autism continued to be identified as part of the same 10-condition checklist, but the previous wording used to name the condition (“autism”) was 

modified to “autism/autism spectrum disorder.” In 2014, the wording was expanded to include “autism, Asperger’s disorder, pervasive developmental disorder, and 

autism spectrum disorder”; the question was no longer part of a condition checklist; and the placement of the autism spectrum disorder question changed within the 

survey questionnaire. Differences observed in estimates before and after these changes may be partially or fully attributable to these changes. 

SOURCE: CDC/NCHS, National Health Interview Survey, 1997–2014. 

 

 

 

 

 

 

 

 

Figure 3. Estimated lifetime prevalence of children aged 3–17 years with parent-reported diagnosis of autism spectrum disorder, by

survey year: United States, 1997–2014

sampling error (24). Given ongoing

concerns about bias in telephone

surveys, NSCH has been redesigned by

the federal Maternal and Child Health

Bureau (its longtime sponsor) to be a

mail- and Web-based survey, and it will

be conducted by the U.S. Census

Bureau starting in 2016.

The ADDM Network conducts ASD

surveillance among 8-year-old children

in multiple geographically defined areas

of the United States in even-numbered

years beginning in 2000 (12,27–31). In

2010, ADDM Network study areas

covered 360,000 8-year-olds. Its

surveillance protocol was developed

from previous ASD surveillance studies

that CDC conducted in metropolitan

Atlanta, Georgia, in 1996, and Brick

Township, New Jersey, in 1998 (32,33).

Unlike NHIS and NSCH, ADDM

Network is not a parent-based survey.

Rather, ADDM Network determines

ASD case status through the review of

children’s medical and educational

records. Trained clinicians determine

whether the records contain documented

symptoms that are consistent with the

DSM-IV-TR criteria for Autistic

Disorder, Asperger’s Disorder, or

Pervasive Developmental Disorder Not

Otherwise Specified. This process

allows the surveillance system to

classify children who have ASD

symptoms, even if they do not have a

previous ASD diagnosis (approximately

20% of the ASD cases identified in

2010). The large, population-based

surveillance areas allow for analyses of

select risk factors and small subgroups.

They also allow for comparisons of

prevalence between different geographic

regions.

Each system has captured similar

prevalence increases since its inception.

For example, ADDM Network estimates

rose from 6.7 per 1,000 children aged 8

years in 2000 and 2002 to 14.7 per

1,000 children aged 8 years in 2010.

NSCH estimates also rose from 5.5 per

1,000 children in 2003 to 20.0 per 1,000

children in 2011. Finally, NHIS

estimates rose in the last decade, as

shown in Figure 3. There has been

strong concordance between estimates

from these three systems (including

similar increases in prevalence following

changes to the ASD case definition in

NSCH and NHIS [20]) despite

differences in their methods and

samples. Parent-reported autism

prevalence estimates from the 2003

NSCH were similar to the estimates

from the 2003–2004 NHIS; both surveys

asked about lifetime diagnosis of

‘‘autism,’’ and prevalence for children

aged 4–17 years was 5.7 per 1,000 in

NHIS and 5.5 per 1,000 in NSCH (25).

Moreover, estimates from the 2007

NSCH (11.0 per 1,000 children aged

3–17 years using an expanded question

about current ‘‘autism, Asperger’s

disorder, pervasive developmental

disorder, or other autism spectrum

disorder’’) were comparable to the

ADDM Network’s medical and

educational records-based estimates

from 2008 (11.3 per 1,000 children aged

8 years) (26,31).

Table A includes the most recent

prevalence estimates from each of the
Page 8	 National Health Statistics Reports n Number 87 n November 13, 2015

Table B. Estimated lifetime prevalence (and standard errors) of autism spectrum disorder

three systems. It is important to among children aged 3–17 years, by sociodemographic characteristics: United States,

2014 remember that relative to the 2014

NHIS data, NSCH data are 2 years older

(2011–2012) and ADDM Network data

are 4 years older (2010). In this context,

the 2014 NHIS estimate (22.4 per 1,000

children aged 3–17 years), which used a

case definition of ASD that was

virtually identical to that used in the

2011–2012 NSCH, seems more realistic

than the 2011–2013 NHIS estimate

(12.5 per 1,000 children aged 3–17

years), which was lower than the latest

estimates from both NSCH and the

ADDM Network. To the extent that

converging estimates with other ASD

tracking systems indicates validity, these

comparisons suggest that ASD

prevalence estimates based on the 2014

NHIS data are more likely to be valid

than estimates based on the 2011–2013

NHIS data. Estimates of ASD

prevalence from the 2014 NHIS are

presented by sociodemographic

characteristics in Table B.

Conclusions

This report examines the prevalence

of developmental disabilities in NHIS

from 2011 through 2014. The findings

suggest that changes to the ordering and

wording of the developmental

disabilities questions within NHIS

resulted in changes to the parentreported prevalence of ASD and any

other DD. Starting in 2016, NHIS will

include questions on the current

prevalence of ID, ASD, and other DD.

This addition will follow the existing

developmental disabilities questions, so

as not to disrupt analyses of trends since

2014, and it will help to align NHIS

estimates with other surveillance efforts,

and minimize the potential for

misdiagnosed cases to be captured

within prevalence estimates.

References

1.Boulet SL, Boyle CA, Shieve LA.

Health care use and health and

functional impact of developmental

disabilities among US children,

1997–2005. Arch Pediatr Adolesc

Med 163(1):19–26. 2009.

Characteristic	 2014

Age (years)

3–10 ......................... 2.34 (0.26)
 

11–17 ......................... 2.13 (0.24)
 

Sex

Male .......................... 3.29 (0.30)
 

Female ........................ 1.15 (0.20)
 

Race and ethnicity

Non-Hispanic white ................. 2.55 (0.29)
 

Non-Hispanic black ................. 2.21 (0.43)
 

Non-Hispanic other ................. 2.49 (0.62)
 

Hispanic........................ 1.49 (0.26)
 

Health insurance coverage type

Private......................... 2.17 (0.25)
 

Public ......................... 2.36 (0.28)
 

Other ......................... *3.90 (1.67)
 

Uninsured....................... *1.32 (0.61)
 

Family structure

Two parent ...................... 2.25 (0.24)
 

Single parent..................... 2.21 (0.29)
 

Other ......................... *2.44 (0.85)
 

Poverty status

Less than 100% ................... 2.17 (0.35)
 

100%–199% ..................... 2.45 (0.37)
 

200%–399% ..................... 2.61 (0.44)
 

400% or more .................... 1.86 (0.31)
 

Parent’s education

High school diploma or GED1 or less ...... 2.28 (0.31)

More than high school ............... 2.23 (0.23)

MSA2 status

Large MSA ...................... 2.30 (0.25)
 

Small MSA ...................... 2.47 (0.34)
 

Not in MSA...................... 1.48 (0.35)
 

Geographic region

Northeast ....................... 3.17 (0.56)
 

Midwest ........................ 2.62 (0.40)
 

South ......................... 1.81 (0.26)
 

West .......................... 2.00 (0.36)
 

* Estimate does not meet standards of reliability or precision (relative standard error is greater than 30% and less than or equal
 

to 50%) and should be used with caution.
 1General Educational Development high school equivalency diploma.
 2Metropolitan statistical area.
 

SOURCE: CDC/NCHS, National Health Interview Survey, 2014.

2.Coo H, Ouelette-Kuntz H, Lloyd JE, Am J Med Genet B Neuropsychiatr

Kasmara L, Holden JJ, Lewis ME. Genet 168(7):600–8. 2015.

Trends in autism prevalence: 4. Shattuck PT. The contribution of

Diagnostic substitution revisited. J diagnostic substitution to the growing

Autism Dev Disord 38(6):1036– administrative prevalence of autism

1046. 2008. in US special education. Pediatrics

3.Polyak A, Kubina RM, Girirajan S. 117(4):1028–37. 2006.

Comorbidity of intellectual disability 5. Leonard H, Dixon G, Whitehouse

confounds ascertainment of autism: AJO, Bourke J, Aiberti K, Nassar N,

Implications for genetic diagnosis. et al. Unpacking the complex nature
National Health Statistics Reports n Number 87 n November 13, 2015 Page 9

of the autism epidemic. Res Autism increase? Development and 26. Kogan MD, Blumberg SJ, Schieve

Spectr Disord 4(4):548–54. 2010. application of a mathematical LA, Boyle CA, Perrin JM, Ghandour

6. Cannell C, Miller P, Oksenberg L. assessment model. Ann Epidemiol RM, et al. Prevalence of parentResearch on interviewing techniques. 21(12):930–45. 2011. reported diagnosis of autism

In: Leinhardt S, editor. Sociological 17. Strack F, Schwarz N, Wanke M. spectrum disorder among children in

methodology. San Francisco, CA: Semantic and pragmatic aspects of the US, 2007. Pediatrics

Jossey-Bass, 389–437. 1981. context effects in social and 124(5):1395–403. 2009.

7. Tourangeau R, Rips LJ, Rasinski K. psychological research. Soc Cogn 27. Autism and Developmental

The psychology of survey response. 9(1):111–25. 1991. Disabilities Monitoring Network

Cambridge, UK: Cambridge 18. Barnett J, Nigg C, De Bourdeaudhuij Surveillance Year 2000 Principal

University Press. 2000. I, Maglione C, Maddock J. The Investigators, CDC. Prevalence of

8. Durkin MS, Maenner MJ, Meaney effect of item order on physical autism spectrum disorders—Autism

FJ, Levy SE, DiGuiseppi C, Nicholas activity estimates using the IPAQ. and Developmental Disabilities

JS, et al. Socioeconomic inequality in Calif J Health Promot 5(1):23–9. Monitoring Network, six sites,

the prevalence of autism spectrum 2007. United States, 2000. MMWR Surveill

disorder: Evidence from a U.S. 19. Kieffer JM, Hoogstraten J. Item- Summ 56(1):1–11. 2007.

cross-sectional study. PLoS One order effects in the Oral Health 28. Autism and Developmental

5(7):e11551. 2010. Impact Profile (OHIP). Eur J Oral Disabilities Monitoring Network

9. MacFarlane JR, Kanaya T. What Sci 116(3):245–9. 2008. Surveillance Year 2002 Principal

does it mean to be autistic? Inter­ 20. Schieve LA, Rice C, Yeargin-Allsopp Investigators, CDC. Prevalence of

state variation in special education M, Boyle CA, Kogan MD, Drews C, autism spectrum disorders—Autism

criteria for autism services. J Child Devine O. Parent-reported prevalence and Developmental Disabilities

Fam Stud 18(6):662–9. 2009. of autism spectrum disorders in Monitoring Network, 14 sites, United

10. Maenner MJ, Durkin MS. Trends in US-born children: An assessment of States, 2002. MMWR Surveill Summ

the prevalence of autism on the basis changes within birth cohorts from the 56(1):12–28. 2007.

of special education data. Pediatrics 2003 to the 2007 National Survey of 29. Autism and Developmental

126(5):1018–25. 2010. Children’s Health. Matern Child Disabilities Monitoring Network

11. Van Handel MM, Branson BM. Health J 16(S1):S151–7. 2012. Surveillance Year 2004 Principal

Monitoring HIV testing in the United 21. Blumberg SJ, Zablotsky B, Avila Investigators, CDC. Brief update:

States: Consequences of methodology RM, Colpe LJ, Pringle BA, Kogan Prevalence of autism spectrum

changes to national surveys. PLoS MD. Diagnosis lost: Differences disorders (ASDs)—Autism and

One 10(4):e0125637. 2015. between children who had and who Developmental Disabilities

12. Autism and Developmental currently have an autism spectrum Monitoring Network, United States,

Disabilities Monitoring Network disorder diagnosis. Autism. 2015 2004. MMWR Surveill Summ

Surveillance Year 2010 Principal [Forthcoming]. 58(SS10):21–4. 2009.

Investigators, CDC. Prevalence of 22. Maenner MJ, Rice CE, Arneson CL, 30. Autism and Developmental

autism spectrum disorder among Cunniff C, Schieve LA, Carpenter Disabilities Monitoring Network

children aged 8 years—Autism and LA, et al. Potential impact of Surveillance Year 2006 Principal

Developmental Disabilities DSM–5 criteria on autism spectrum Investigators, CDC. Prevalence of

Monitoring Network, 11 sites, United disorder prevalence estimates. JAMA autism spectrum disorders—Autism

States, 2010. MMWR Surveill Summ Psychiatry 71(3):292–300. 2014. and Developmental Disabilities

63(2):1–21. 2014. 23. Boyle CA, Boulet S, Schieve LA, Monitoring Network, United States,

13. American Psychiatric Association. Cohen RA, Blumberg SJ, Yeargin­ 2006. MMWR Surveill Summ

Diagnostic and statistical manual of Allsopp M, et al. Trends in the 58(10):1–20. 2009.

mental disorders, fourth edition, text prevalence of developmental 31. Autism and Developmental

revision. Washington, DC: 2000. disabilities in US children. Pediatrics Disabilities Monitoring Network

14. Parsons VL, Moriarity C, Jonas K, et 127(6):1034–42. 2011. Surveillance Year 2008 Principal

al. Design and estimation for the 24. Blumberg SJ, Bramlett MD, Kogan Investigators, CDC. Prevalence of

National Health Interview Survey, MD, et al. Changes in prevalence of autism spectrum disorders—Autism

2006–2015. National Center for parent-reported autism spectrum and Developmental Disabilities

Health Statistics. Vital Health Stat disorder in school-aged U.S. Monitoring Network, 14 sites, United

2(165). 2014. children: 2007 to 2011–2012. States, 2008. MMWR Surveill Summ

15. RTI International. SUDAAN National health statistics reports; no 61(3):1–19. 2012.

(Release 11.0.0) [computer software]. 65. Hyattsville, MD: National Center

2012. for Health Statistics. 2013.

16. Schieve LA, Rice C, Devine O, 25. CDC. Mental health in the United

Maenner MJ, Lee LC, Fitzgerald R, States: Parental report of diagnosed

et al. Have secular changes in autism in children aged 4–17

perinatal risk factors contributed to years—United States, 2003–2004.

the recent autism prevalence MMWR Morb Mortal Wkly Rep

55(17):481–6. 2006.
Page 10 National Health Statistics Reports n Number 87 n November 13, 2015

32. Bertrand J, Mars A, Boyle C, Bove

F, Yeargin-Allsopp M, Decoufle P.

Prevalence of autism in a United

States population: The Brick

Township, New Jersey, investigation.

Pediatrics 108(5):1155–61. 2001.

33. Yeargin-Allsopp M, Rice C,

Karapurkar T, Doernberg N, Boyle

C, Murphy C. Prevalence of autism

in a US metropolitan area. JAMA

289(1):49–55. 2003.
National Health Statistics Reports n Number 87 n November 13, 2015 Page 11

Table 1. Percentages (and standard errors) of sociodemographic characteristics among children aged 3–17 years ever diagnosed with

autism spectrum disorder, by survey year: United States, 2011–2013 and 2014

Characteristic 2011–20131 20141

Age (years)

3–10 .............................. 55.4 (2.9) 55.4 (4.0)

11–17 .............................. 44.6 (2.9) 44.6 (4.0)

Sex

Male............................... 81.7 (2.3) 75.0 (3.7)

Female ............................. 18.3 (2.3) 25.0 (3.7)

Race and ethnicity

Non-Hispanic white...................... 58.9 (2.8) 59.9 (4.0)

Non-Hispanic black...................... 11.6 (1.8) 13.5 (2.5)

Non-Hispanic other...................... 9.2 (1.5) 10.6 (2.6)

Hispanic ............................ 20.3 (2.2) 16.1 (2.7)

Health insurance coverage type

Private ............................. 52.5 (2.9) 52.7 (4.1)

Public .............................. 38.3 (2.9) 39.3 (3.9)

Other .............................. 4.1 (1.0) *4.7 (1.9)

Uninsured ........................... 5.1 (1.2) *3.4 (1.5)

Family structure

Two parent ........................... 65.9 (2.7) 68.0 (3.7)

Single parent ......................... 31.0 (2.7) 28.7 (3.6)

Other .............................. 3.1 (0.9) *3.3 (1.1)

Poverty status

Less than 100%........................ 20.2 (2.3) 21.5 (3.2)

100%–199% .......................... 23.1 (2.7) 25.1 (3.5)

200%–399% .......................... 32.3 (2.8) 32.1 (4.3)

400% or more ......................... 24.5 (2.7) 21.4 (3.3)

Parent’s education

High school diploma or GED2 or less .......... 24.0 (2.5) 32.4 (3.9)

More than high school .................... 76.0 (2.5) 67.6 (3.9)

MSA3 status

Large MSA........................... 58.0 (2.9) 54.7 (4.2)

Small MSA........................... 30.2 (2.6) 36.1 (4.0)

Not in MSA .......................... 11.8 (1.8) 9.2 (2.2)

Geographic region

Northeast............................ 15.0 (2.1) 21.0 (3.4)

Midwest............................. 22.6 (2.5) 26.2 (3.5)

South .............................. 37.6 (2.9) 31.2 (3.7)

West............................... 24.8 (2.4) 21.5 (3.4)

* Estimate does not meet standards of reliability or precision (relative standard error is greater than 30% and less than or equal to 50%) and should be used with caution.
 1Sample sizes of children with autism spectrum disorder were 433 in 2011–2013 and 237 in 2014.
 2General Educational Development high school equivalency diploma.
 3Metropolitan statistical area.
 

SOURCE: CDC/NCHS, National Health Interview Survey, 2011–2013 and 2014.
Page 12 National Health Statistics Reports n Number 87 n November 13, 2015

Table 2. Percentages (and standard errors) of selected co-occurring conditions, functional limitations, and service utilization among

children aged 3–17 years ever diagnosed with autism spectrum disorder, by survey year: United States, 2011–2013 and 2014

Characteristic 2011–20131 20141

Co-occurring conditions

Attention-deficit/hyperactivity disorder ............... 45.3 (3.0) 42.8 (4.1)

Intellectual disability .......................... 23.2 (2.5) 16.7 (3.1)

Learning disability ........................... 63.2 (2.8) 62.6 (3.9)

Other developmental delay...................... 66.7 (2.8) †

22.9 (3.6)

Seizures, past 12 months ...................... *3.0 (0.9) *3.1 (1.2)

Stuttered or stammered, past 12 months ............. 10.2 (1.8) 8.1 (2.1)

Limitations

Trouble seeing ............................. 4.9 (1.1) *7.1 (2.2)

Trouble hearing............................. 8.3 (1.5) *5.7 (1.8)

Difficulty walking without equipment ................ *2.4 (0.8) *0.9 (0.5)

Difficulty remembering ........................ 12.7 (2.1) 7.4 (2.1)

Needs help with personal care ................... 19.9 (2.4) 18.9 (3.2)

Any impairment noted ......................... 83.5 (2.1) 78.2 (3.2)

Services

Receives special education or early intervention services . . . 78.3 (2.4) 69.9 (3.8)

Home care from health professional, past 12 months ..... 5.1 (1.1) *5.1 (1.9)

† p < 0.001.

* Estimate does not meet standards of reliability or precision (relative standard error is greater than 30% and less than or equal to 50%) and should be used with caution. 1Sample sizes of children with autism spectrum disorder were 433 in 2011–2013 and 237 in 2014.

SOURCE: CDC/NCHS, National Health Interview Survey, 2011–2013 and 2014.
National Health Statistics Reports n Number 87 n November 13, 2015 Page 13

Table 3. Percentages (and standard errors) of sociodemographic characteristics among children aged 3–17 years ever diagnosed with

other developmental delay, by survey year: United States, 2011–2013 and 2014

Characteristic 2011–20131 20141

Age (years)

3–10 .............................. 56.8 (1.8) 58.9 (3.3)

11–17 .............................. 43.2 (1.8) 41.1 (3.3)

Sex

Male............................... 65.4 (1.7) 63.3 (3.2)

Female ............................. 34.6 (1.7) 36.7 (3.2)

Race and ethnicity

Non-Hispanic white...................... 61.6 (1.7) 59.9 (3.3)

Non-Hispanic black...................... 13.7 (1.1) 12.4 (2.0)

Non-Hispanic other...................... 7.3 (0.8) 9.7 (1.9)

Hispanic ............................ 17.4 (1.2) 18.0 (2.4)

Health insurance coverage type

Private ............................. 48.0 (1.7) 46.4 (3.3)

Public .............................. 43.5 (1.7) 44.5 (3.1)

Other .............................. 3.8 (0.7) 5.7 (1.6)

Uninsured ........................... 4.6 (0.8) *3.4 (1.1)

Family structure

Two parent ........................... 62.8 (1.6) 63.0 (3.0)

Single parent ......................... 34.0 (1.6) 32.9 (2.9)

Other .............................. 3.2 (0.5) 4.1 (1.2)

Poverty status

Less than 100%........................ 27.7 (1.6) 25.9 (3.0)

100%–199% .......................... 22.0 (1.5) 26.5 (3.0)

200%–399% .......................... 25.9 (1.4) 25.9 (3.1)

400% or more ......................... 24.4 (1.5) 21.7 (2.9)

Parent’s education

High school diploma or GED2 or less .......... 29.9 (1.5) 28.9 (3.1)

More than high school .................... 70.1 (1.5) 71.1 (3.1)

MSA3 status

Large MSA........................... 52.4 (1.9) 53.4 (3.5)

Small MSA........................... 32.1 (1.7) 33.6 (3.3)

Not in MSA .......................... 15.5 (1.4) 12.9 (2.5)

Geographic region

Northeast............................ 19.2 (1.5) 18.1 (2.6)

Midwest............................. 24.1 (1.5) 27.4 (3.3)

South .............................. 37.0 (1.7) 36.6 (3.4)

West............................... 19.7 (1.3) 17.9 (2.4)

* Estimate does not meet standards of reliability or precision (relative standard error is greater than 30% and less than or equal to 50%) and should be used with caution.
 1Sample sizes of children with other developmental delay were 1,486 in 2011–2013 and 420 in 2014.
 2General Educational Development high school equivalency diploma.
 3Metropolitan statistical area.
 

SOURCE: CDC/NCHS, National Health Interview Survey, 2011–2013 and 2014.
Page 14 National Health Statistics Reports n Number 87 n November 13, 2015

Table 4. Percentages (and standard errors) of selected co-occurring conditions, functional limitations, and service utilization among

children aged 3–17 years ever diagnosed with other developmental delay, by survey year: United States, 2011–2013 and 2014

Characteristic 2011–20131 20141

Co-occurring conditions

Attention-deficit/hyperactivity disorder ............... 30.5 (1.5) 27.4 (2.8)

Intellectual disability .......................... 14.4 (1.1) 12.9 (2.2)

Learning disability ........................... 53.7 (1.6) 56.5 (3.4)

Autism spectrum disorder ...................... 17.2 (1.1) 14.4 (2.3)

Seizures, past 12 months ...................... 4.8 (0.7) 5.8 (1.5)

Stuttered or stammered, past 12 months ............. 9.3 (1.0) 13.1 (2.4)

Limitations

Trouble seeing ............................. 8.3 (1.0) 8.7 (1.8)

Trouble hearing............................. 9.2 (1.1) 9.5 (2.0)

Difficulty walking without equipment ................ 3.6 (0.6) *4.2 (1.6)

Difficulty remembering ........................ 5.5 (0.7) 5.6 (1.3)

Needs help with personal care ................... 10.6 (1.0) 14.4 (2.4)

Any impairment noted ......................... 63.9 (1.6) 61.7 (3.4)

Services

Receives special education or early intervention services . . . 58.1 (1.7) 56.4 (3.5)

Home care from health professional, past 12 months ..... 5.2 (0.7) *3.6 (1.2)

* Estimate does not meet standards of reliability or precision (relative standard error is greater than 30% and less than or equal to 50%) and should be used with caution. 1Sample sizes of children with other developmental delay were 1,486 in 2011–2013 and 420 in 2014.

SOURCE: CDC/NCHS, National Health Interview Survey, 2011–2013 and 2014.
National Health Statistics Reports n Number 87 n November 13, 2015 Page 15

Table 5. Percentages (and standard errors) of sociodemographic characteristics among children aged 3–17 years ever diagnosed with

autism spectrum disorder or other developmental delay, by survey year: United States, 2011–2013 and 2014

Characteristic 2011–20131 20141

Age (years)

3–10 ............................ 56.0 (1.7) 57.9 (2.7)

11–17............................ 44.0 (1.7) 42.1 (2.7)

Sex

Male ............................ 67.0 (1.6) 66.7 (2.6)

Female........................... 33.0 (1.6) 33.3 (2.6)

Race and ethnicity

Non-Hispanic white ................... 61.4 (1.6) 59.8 (2.6)

Non-Hispanic black ................... 13.8 (1.0) 13.1 (1.6)

Non-Hispanic other ................... 7.4 (0.7) 10.3 (1.7)

Hispanic .......................... 17.4 (1.1) 16.8 (1.9)

Health insurance coverage type

Private ........................... 48.1 (1.7) 49.3 (2.7)

Public............................ 43.3 (1.6) 42.5 (2.6)

Other ........................... 3.8 (0.7) 4.7 (1.2)

Uninsured ......................... 4.8 (0.8) 3.5 (1.0)

Family structure

Two parent ........................ 63.0 (1.5) 64.7 (2.4)

Single parent ....................... 33.7 (1.5) 31.5 (2.3)

Other ............................ 3.3 (0.5) 3.9 (0.9)

Poverty status

Less than 100% ..................... 27.2 (1.5) 24.2 (2.3)

100%–199% ....................... 22.6 (1.4) 25.0 (2.4)

200%–399% ....................... 26.3 (1.4) 29.0 (2.8)

400% or more ...................... 24.0 (1.4) 21.8 (2.3)

Parent’s education

High school diploma or GED2 or less ........ 29.8 (1.4) 29.8 (2.5)

More than high school ................. 70.2 (1.4) 70.2 (2.5)

MSA3 status

Large MSA ........................ 52.7 (1.8) 53.5 (2.9)

Small MSA ........................ 32.0 (1.7) 34.4 (2.7)

Not in MSA ........................ 15.2 (1.4) 12.1 (2.0)

Geographic region

Northeast ......................... 18.9 (1.4) 19.3 (2.2)

Midwest .......................... 24.2 (1.4) 26.3 (2.6)

South............................ 36.7 (1.6) 35.0 (2.7)

West ............................ 20.2 (1.3) 19.3 (2.0)

1Sample sizes of children with autism spectrum disorder or other developmental delay were 1,630 in 2011–2013 and 607 in 2014.
 2General Educational Development high school equivalency diploma.
 3Metropolitan statistical area.
 

SOURCE: CDC/NCHS, National Health Interview Survey, 2011–2013 and 2014.
Page 16 National Health Statistics Reports n Number 87 n November 13, 2015

Table 6. Percentages (and standard errors) of selected co-occurring conditions, functional limitations, and service utilization among

children aged 3–17 years ever diagnosed with autism spectrum disorder or other developmental delay, by survey year: United States,

2011–2013 and 2014

Characteristic 2011–20131 20141

Co-occurring conditions

Attention-deficit/hyperactivity disorder ............... 31.5 (1.4) 32.1 (2.5)

Intellectual disability .......................... 15.0 (1.1) 12.2 (1.7)

Learning disability ........................... 53.7 (1.5) 56.3 (2.7)

Seizures, past 12 months ...................... 4.5 (0.7) 4.3 (1.0)

Stuttered or stammered, past 12 months ............. 9.1 (0.9) 10.9 (1.8)

Limitations

Trouble seeing ............................. 8.1 (0.9) 7.3 (1.4)

Trouble hearing............................. 8.6 (1.0) 8.1 (1.5)

Difficulty walking without equipment ................ 3.4 (0.5) *2.9 (1.1)

Difficulty remembering ........................ 6.1 (0.8) 5.4 (1.1)

Needs help with personal care ................... 10.6 (1.0) 14.6 (2.0)

Any impairment noted ......................... 64.8 (1.6) 65.3 (2.6)

Services

Receives special education or early intervention services . . . 59.3 (1.6) 58.5 (2.8)

Home care from health professional, past 12 months ..... 5.2 (0.7) 4.2 (1.1)

* Estimate does not meet standards of reliability or precision (relative standard error is greater than 30% and less than or equal to 50%) and should be used with caution. 1Sample sizes of children with autism spectrum disorder or other developmental delay were 1,630 in 2011–2013 and 607 in 2014.

SOURCE: CDC/NCHS, National Health Interview Survey, 2011–2013 and 2014.
National Health Statistics Reports n Number 87 n November 13, 2015 Page 17

Table 7. Percentages (and standard errors) of sociodemographic characteristics among children aged 3–17 years ever diagnosed with

intellectual disability, autism spectrum disorder, or any other developmental delay, by survey year: United States, 2011–2013 and 2014

Characteristic 2011–20131 20141

Age (years)

3–10 .............................. 54.0 (1.6) 55.9 (2.6)

11–17 .............................. 46.0 (1.6) 44.1 (2.6)

Sex

Male............................... 66.8 (1.5) 65.6 (2.4)

Female ............................. 33.2 (1.5) 34.4 (2.4)

Race and ethnicity

Non-Hispanic white...................... 60.0 (1.5) 59.5 (2.5)

Non-Hispanic black...................... 14.5 (1.0) 13.3 (1.6)

Non-Hispanic other...................... 7.2 (0.7) 9.9 (1.5)

Hispanic ............................ 18.2 (1.1) 17.3 (1.8)

Health insurance coverage type

Private ............................. 46.7 (1.6) 49.0 (2.6)

Public .............................. 44.8 (1.6) 43.3 (2.5)

Other .............................. 3.9 (0.7) 4.3 (1.1)

Uninsured ........................... 4.6 (0.7) 3.4 (0.9)

Family structure

Two parent ........................... 61.0 (1.5) 63.6 (2.3)

Single parent ......................... 35.4 (1.4) 32.3 (2.2)

Other .............................. 3.6 (0.5) 4.0 (0.9)

Poverty status

Less than 100%........................ 27.1 (1.4) 24.9 (2.3)

100%–199% .......................... 23.3 (1.4) 24.6 (2.3)

200%–399% .......................... 26.8 (1.3) 28.6 (2.6)

400% or more ......................... 22.8 (1.3) 22.0 (2.2)

Parent’s education

High school diploma or GED2 or less .......... 31.3 (1.4) 30.4 (2.4)

More than high school .................... 68.7 (1.4) 69.6 (2.4)

MSA3 status

Large MSA........................... 52.7 (1.7) 53.9 (2.8)

Small MSA........................... 31.6 (1.6) 34.3 (2.6)

Not in MSA .......................... 15.7 (1.3) 11.9 (1.9)

Geographic region

Northeast............................ 18.7 (1.4) 18.6 (2.0)

Midwest............................. 23.8 (1.3) 25.4 (2.4)

South .............................. 37.0 (1.5) 36.3 (2.6)

West............................... 20.5 (1.2) 19.7 (2.1)

1Sample sizes of children with intellectual disability, autism spectrum disorder, or any other developmental delay were 1,789 in 2011–2013 and 660 in 2014.
 2General Educational Development high school equivalency diploma.
 3Metropolitan statistical area.
 

SOURCE: CDC/NCHS, National Health Interview Survey, 2011–2013 and 2014.
Page 18 National Health Statistics Reports n Number 87 n November 13, 2015

Table 8. Percentages (and standard errors) of selected co-occurring conditions, functional limitations, and service utilization among

children aged 3–17 years ever diagnosed with intellectual disability, autism spectrum disorder, or any other developmental delay, by

survey year: United States, 2011–2013 and 2014

Characteristic 2011–20131 20141

Co-occurring conditions

Attention-deficit/hyperactivity disorder ............... 32.9 (1.4) 32.7 (2.3)

Learning disability ........................... 55.9 (1.5) 58.3 (2.6)

Seizures, past 12 months ...................... 4.6 (0.7) 4.4 (1.0)

Stuttered or stammered, past 12 months ............. 9.4 (0.9) 11.0 (1.7)

Limitations

Trouble seeing ............................. 8.3 (0.9) 8.2 (1.4)

Trouble hearing............................. 8.7 (0.9) 8.2 (1.4)

Difficulty walking without equipment ................ 3.4 (0.5) *2.9 (1.0)

Difficulty remembering ........................ 6.3 (0.7) 5.5 (1.1)

Needs help with personal care ................... 11.2 (0.9) 13.9 (1.8)

Any impairment noted ......................... 65.3 (1.5) 66.4 (2.4)

Services

Receives special education or early intervention services . . . 59.7 (1.6) 59.5 (2.6)

Home care from health professional, past 12 months ..... 4.9 (0.7) 3.8 (1.0)

* Estimate does not meet standards of reliability or precision (relative standard error is greater than 30% and less than or equal to 50%) and should be used with caution. 1Sample sizes of children with intellectual disability, autism spectrum disorder, or any other developmental delay were 1,789 in 2011–2013 and 660 in 2014.

SOURCE: CDC/NCHS, National Health Interview Survey, 2011–2013 and 2014.
National Health Statistics Reports n Number 87 n November 13, 2015 Page 19

Technical Notes

Definition of terms

Age—Categorized as 3–10 years or

11–17 years based on the child’s age at

the time of the interview.

Race and ethnicity—Based on two

separate and distinct questions that

determine Hispanic or Latino origin and

race. Persons of Hispanic or Latino

origin may be of any race. Hispanic or

Latino origin includes persons of

Mexican, Puerto Rican, Cuban, Central

and South American, or Spanish origin.

Race is based on the family

respondent’s description of his or her

own racial background, as well as the

racial background of other family

members. Race and ethnicity was

categorized as non-Hispanic white

(single race), non-Hispanic black (single

race), non-Hispanic other (including

multiple races), and Hispanic (any race

or races). Estimates for non-Hispanic

persons of races other than white only,

black only, and Asian only, or of

multiple races, are not reported.

Health insurance coverage type—

Includes private, public, other, or

uninsured. Public health insurance

includes children with Medicaid,

Children’s Health Insurance Program, or

other state-sponsored health plan. Other

health insurance includes children with

Medicare, military health coverage, or

other government programs. Uninsured

children includes those who were not

reported to have been covered at the

time of interview or those who were

covered only by Indian Health Service

or had only a single service plan (e.g.,

dental care only). Children with more

than one type of health insurance were

assigned to the first appropriate category

in the following mutually exclusive

hierarchy: private coverage, public

coverage, other coverage, or uninsured.

Family structure—Based on the

parent(s) living in the household with

the child. Family structure was

categorized as two parent, single parent,

or other. Two-parent families can

include biological, adoptive, step-, or

foster parents. Legal guardians are not

classified as parents. Other includes

children with neither a mother nor a

father living in the household.

Poverty status—Based on the ratio

of the family’s income in the previous

calendar year to the appropriate poverty

threshold (given the family’s size and

number of children) defined by the U.S.

Census Bureau for that year. Estimates

are based on the reported income only

and may differ from estimates produced

with both reported and imputed income.

Parent’s education—Based on the

highest grade completed by the child’s

mother or father who was living in the

household, regardless of that parent’s

age. This does not take into account a

parent’s education if they did not live in

the same household as the child.

MSA status—Categorized as inside a

large metropolitan statistical area (MSA),

small MSA, or not in an MSA. Large

MSA is defined as a county or group of

contiguous counties with a population of

1 million or more, while small MSA is

defined as a population of less than

1 million.

Geographic region—In the

geographic classification of the U.S.

population, states are grouped into the

four regions used by the U.S. Census

Bureau:

Region States included

Northeast Maine, Vermont, New

Hampshire, Massachusetts,

Connecticut, Rhode Island,

New York, New Jersey, and

Pennsylvania

Midwest Ohio, Illinois, Indiana,

Michigan, Wisconsin,

Minnesota, Iowa, Missouri,

North Dakota, South Dakota,

Kansas, and Nebraska

South Delaware, Maryland, District

of Columbia, West Virginia,

Virginia, Kentucky,

Tennessee, North Carolina,

South Carolina, Georgia,

Florida, Alabama, Mississippi,

Louisiana, Oklahoma,

Arkansas, and Texas

West Washington, Oregon,

California, Nevada, New

Mexico, Arizona, Idaho,

Utah, Colorado, Montana,

Wyoming, Alaska, and

Hawaii

Attention-deficit/hyperactivity

disorder—Based on a positive response

to the survey question, ‘‘Has a doctor or

health professional ever told you that

[child’s name] had attention-deficit/

hyperactivity disorder (ADHD) or

attention deficit disorder (ADD)?’’

Learning disability—Based on a

positive response to the survey question,

‘‘Has a representative from a school or

a health professional ever told you that

[child’s name] had a learning

disability?’’

Seizures—Based on a positive

response to the survey question,

‘‘During the past 12 months, has [child’s

name] had any of the following

conditions. . . seizures?’’

Stuttered or stammered—Based on a

positive response to the survey question,

‘‘During the past 12 months, has [child’s

name] had any of the following

conditions. . . stuttering or

stammering?’’

Trouble seeing—Based on a positive

response to the survey question, ‘‘Does

[child’s name] have any trouble seeing

even when wearing glasses or contact

lenses?’’

Trouble hearing—Respondents were

asked to describe the child’s hearing

without the use of hearing aids or other

listening devices. Based on the survey

question, ‘‘Which statement best

describes [child’s name’s] hearing:

excellent, good, a little trouble hearing,

moderate trouble, a lot of trouble, or is

[child’s name] deaf?’’ Responses of ‘‘a

little trouble hearing,’’ ‘‘moderate

trouble,’’ ‘‘a lot of trouble,’’ and ‘‘deaf’’

were labeled trouble hearing.

Difficulty walking—Based on a

positive response for the sample child to

the survey question, ‘‘Because of a

health problem, does anyone in the

family have difficulty walking without

using any special equipment?’’

Difficulty remembering—Based on a

positive response for the sample child to

the survey question, ‘‘Is anyone in the

family limited in any way because of

difficulty remembering or because they

experience periods of confusion?’’

Needs help with personal

care—Based on a positive response for

the sample child to the survey question,

‘‘Because of a physical, mental, or
Page 20 National Health Statistics Reports n Number 87 n November 13, 2015

emotional problem, does anyone in the

family need the help of other persons

with personal care needs, such as eating,

bathing, dressing, or getting around

inside this home?’’

Any impairment noted—Based on a

positive response for the sample child to

the survey question, ‘‘Are any family

members limited in any way in any

activities because of physical, mental, or

emotional problems?’’

Receives special education or early

intervention services—Based on a

positive response for the sample child to

the survey question, ‘‘Do any of these

family members, [list of children’s

names], receive special educational or

early intervention services?’’

Home care—Based on a positive

response to the survey question,

‘‘During the past 12 months, did

[sample child] receive care at home

from a nurse or other health care

professional?’’
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National Health Statistics Reports n Number 87 n November 13, 2015

Suggested citation

Zablotsky B, Black LI, Maenner MJ, et al.

Estimated prevalence of autism and other

developmental disabilities following

questionnaire changes in the 2014 National

Health Interview Survey. National health

statistics reports; no 87. Hyattsville, MD:

National Center for Health Statistics. 2015.

Copyright information

All material appearing in this report is in the

public domain and may be reproduced or

copied without permission; citation as to

source, however, is appreciated.

National Center for Health Statistics

Charles J. Rothwell, M.S., M.B.A., Director

Nathaniel Schenker, Ph.D., Deputy Director

Jennifer H. Madans, Ph.D., Associate Director

for Science

Division of Health Interview Statistics

Marcie L. Cynamon, Director
 

Stephen J. Blumberg, Ph.D., Associate Director
 

for Science
 

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