Codes and Frequencies
AUTISMEV reports whether the person had autism (1994-1995) or if the person's doctor or other health professional had ever diagnosed him/her with autism (1997-2010) or an autism spectrum disorder (2011 onward). Please see Comparability and Universe tabs for changes in universe and question wording between samples.
In 1994 and 1995, this variable is part of the Disability Supplement (NHIS-D) that collects information on disability. NHIS-D included two household interviews: in Phase I all members of sample families were screened for any indication of disability; in Phase II persons with any indication of disability were followed-up for additional information. Phase I includes sensory, communication, and mobility problems; health conditions; activities of daily living and independent activities of daily living; functional limitations; mental health; services and benefits; special health needs of children; early child development; education; relationship to respondent; and perceived disability. Phase II includes four Disability Followback Survey (DFS) questionnaires: one for children, one for adults, one for elderly persons (69 years of age and over) without any indication of disability (also called the Supplement on Aging or SOA; only in 1994), and one for persons with a history of polio.
The Field Representative's Manuals provided two definitions of autism. The Manual for 1997-2000 noted, "Autism is pronounced (Aw-tizm) and is a developmental disability affecting verbal and nonverbal communication as well as social interaction." The Manual for 2001 forward included a more extensive definition:
These definitions were not routinely shared with respondents.
Changes in universe and question wording affect comparability between samples.
AUTISMEV is comparable for 1994-1995. In those years, this question refers to all persons in the National Health Interview Survey-Disability Survey (NHIS-D) Phase I sample. In those years, this question reports whether the person has autism.
Apart from changes in universe, AUTISMEV is comparable for 1997-2010. From 1997 to 2013, this question was asked of sample children under age 18. In 2014, the universe changed from all sample children to sample children ages 2 to 17.
From 1997 to 2010, the household respondent was asked if he or she had ever been told by a doctor or health professional that the sample child had autism. Beginning in 2011, the term "autism" was replaced with the phrase "autism/autism spectrum disorder" in the list of conditions shown to persons responding to the survey question associated with AUTISMEV. This change limits comparability with responses to AUTISMEV from before 2011, as persons with an autism spectrum disorder (such as Asperger syndrome) would not necessarily have given an affirmative response to the associated survey question when asked only about autism.
In 2014, the phrase "autism/autism spectrum disorder" was replaced with the phrase "Autism, Asperger's disorder, pervasive developmental disorder, or autism spectrum disorder." This change limits comparability with responses to AUTISMEV from 2011 to 2013, as persons with a specific diagnosis (such as Asperger's disorder or pervasive developmental disorder) would not necessarily have given an affirmative response to the associated survey question in previous years. In addition, the universe changed from all sample children to sample children ages 2 to 17.
The NHIS questionnaire was substantially redesigned in 2019 to introduce a different data collection structure and new content. For more information on changes in terminology, universes, and data collection methods beginning in 2019, please see the user note.
- 1994-1995: Persons in the NHIS-D Phase I sample.
- 1997-2006: Sample children under age 18.
- 2007: All sample persons.
- 2008-2013: Sample children under age 18.
- 2014-2018: Sample children ages 2 to 17.
- 2019: Sample children ages 2 to 17.
- 1994-1995, 1997-2019