Since 1957, the National Center for Health Statistics (NCHS) annually conducts a National Health Interview Survey (NHIS) of the U.S. noninstitutionalized civilian population, which consists of approximately 122,000 individuals in 48,000 households. The NHIS consists of a core questionnaire and supplements. The core questionnaire is aimed at a continuous assessment and analysis of health trends in the United States, and its topics--including basic health, socioeconomic, and demographic data--do not vary much across years. Each year, one or more supplements are added to this core questionnaire to reflect public health data needs. Recent supplement topics included cancer risk factors, youth risk behaviors, knowledge and attitudes about AIDS, and child health.

The 1994-1995 National Health Interview Survey on Disability (NHIS-D) was one of the supplements to the 1994 and 1995 NHIS core questionnaires. Due to the low prevalence of disabilities among noninstitutionalized civilians, the NHIS-D was collected over two years, from January 1994 to December 1995. The NHIS-D was designed to meet the need for data on the prevalence and nature of disability in the U.S. since the establishment of the Americans with Disabilities Act (ADA) in 1990. One of the main objectives of the NHIS-D was to develop a survey instrument that would provide useful disability measures while accommodating social, administrative, and medical considerations, so that the data could be analyzed by a variety of agencies and programs. Also, the NHISD was designed to collect data to facilitate public health policy and provide descriptive baseline statistics on the effects of disabilities. The NHIS-D, Phase I questionnaire was administered at the same time as the NHIS core questionnaire and the other supplements. Given the limited amount of time allocated for the disability supplement, the NCHS decided to conduct a two-phase data collection with two separate questionnaires on disability. Eligibility for the NHIS-D, Phase II was based on the responses to the Phase I disability supplement, as well as the core questionnaire topics on activity limitation, and the family resource supplement regarding the receipt of disability benefits. The complete--merged 1994/95--NHIS-D Phase I data and documentation are available as RADIUS dataset 35-36.

The Phase II interviews were conducted six to eight months after the Phase I interviews, beginning in August 1994 and ending in 1997. Interviews using the Adult questionnaire were conducted with the individual identified from the Phase I interview whenever possible. The respondent for the Child component was the parent or the adult in the household who knew the most about the child's health. The NHIS-D, Phase II Child survey includes information on utilization and the need for services, functional assessment, and the impact of the child's disability on the family. The 1994 and 1995 Child surveys were merged and archived by RADIUS staff as Dataset 37-38. Dataset 37-38 contains 1,199 variables and 6,983 cases. The Adult questionnaire obtained extensive information on issues such as employment, transportation needs, personal assistance needs, use of services and benefits, and participation in social activities. The 1994 and 1995 Adult surveys were merged and archived by RADIUS staff as Dataset 39-41. Dataset 39-41 contains 2,534 variables and 25,805 cases. An additional Outcome file, archived as RADIUS Dataset 42, provides information on the response or non-response of Phase I respondents eligible for either the Adult or Child phase II. Dataset 42 contains 4 variables and 202,560 cases. Identification variables are available to link NHIS-D respondents between Phases (I/II) as well as within households (Child/Adult), and to related government-sponsored data collections.