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.")

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).

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.