Codes and Frequencies
For sample adults and sample children, HEALTH rates an individual's general health (as self-reported by the person in question or evaluated by a family member) on a four-point (1972-81) or five-point (1982 forward) Likert scale, ranging from "excellent" to "poor" (along with an unrated "unknown" category).
For 1997-2018, HSTATYR reports whether the health status of sample adults and sample children was better, worse, or about the same as one year ago.
Beginning in 1982, the number of rank-ordered responses for respondents to select from changed from four (excellent, good, fair, and poor) to five (excellent, very good, good, fair, and poor).
The relative frequency of responses more favorable than "fair" (i.e., combining "excellent," "very good," and "good" versus combining "excellent" and "good") is similar before and after 1982. Nonetheless, researchers should exercise care in comparing results before and after 1982. For analyses straddling the 1972-81 and 1982 forward divide, analysts may wish to recode HEALTH dichotomously (comparing persons with "poor" or "fair" health to persons whose health is rated "good" or better, or comparing persons whose health is rated "poor" to persons whose health is rated better than "poor.")
In 1982, the question wording also changed significantly.
For 1972-81, interviewers asked, "Compared to other persons [person's] age, would you say that his health is excellent, good, fair, or poor?" Beginning in 1982, the explicit comparison to persons of the same age was dropped; instead, interviewers asked, "Would you say that [person's] health in general is excellent, very good, good, fair, or poor?" This change may result in loss of comparability before and after 1982 for some age groups (e.g., the oldest-old).
Prior to 1997, all persons for whom health status information was unavailable are grouped together and coded as "Unknown" (code 9). Starting in 1997, the reason why this information was unavailable is specified.
For 1997 forward, the unknown category is reported in terms of "Unknown--refused" (code 7), "Unknown--not ascertained" (code 8), and "Unknown--don't know" (code 9). The value of 9 thus implicitly means "Unknown--for all possible reasons" for 1972-96 and means "Unknown--don't know" for 1997.
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.
- 1972-2018: All persons.
- 2019: Sample adults age 18+ and sample children age 0-17.