United States National Health Interview Survey 1975

Since 1957, the National Health Interview Survey (NHIS) has been a primary source of information on the health of the population of the United States. The NHIS is a cross-sectional household interview survey that is fielded continuously throughout the year. For the 1975 survey, the sample plan included about 116,000 persons from approximately 40,000 households.

A core questionnaire collected data on topics such as acute conditions, injuries, chronic conditions, days of disability, limitation of activity, hospitalization, and demographic information such as housing, family composition, income, etc. For 1975, the survey contained a section on health management organizations and a supplemental survey on family out-of-pocket health expenses.