The original question wording (for 1969-1974) was, "About how long has it been since [person] saw or talked to a medical doctor?" For 1975-81, this wording was retained, but the line, "(Include doctors seen while a patient in a hospital)" was added.

The Field Representative's Manual for 1969-73 specified, "The term 'doctor' covers only medical doctors (MD) and osteopathic physicians (OD)." Moreover, the Manual directed interviewers, "Do not count dentists, optometrists or other practitioners (such as chiropractors) who do not have an MD degree as medical doctors." For 1974-1981, the definition of medical doctor remained the same, but the Field Representative's Manual for those years instructed the interview not to "make a special inquiry about the kind of doctor consulted or tell the respondent the survey definition of who is considered a doctor." Instead, if the respondent volunteered information about having seen some other sort of health professional (e.g., a chiropractor), interviewers were directed to repeat the question, emphasizing "medical" (e.g., "Did you see or talk to a medical doctor?")

Specifically, from 1982 to 1996, interviewers asked, "About how long has it been since [person] last saw or talked to a medical doctor or assistant? Include doctors seen while a patient in a hospital." Beginning in 1997, the question was, "About how long has it been since [you/anyone in the family] last saw or talked to a doctor or other health care professional about [your own/sample child's] health? Include doctors seen while [he/she was] a patient in a hospital." From 1982 forward, then, contact with a health care professional such as a nurse practitioner in a clinic or doctor's office counted, which was not the case earlier. Researchers should therefore be cautious about comparing results from before and after 1982.

Beginning in 1982, the Manual stated that the terms "medical doctor" and "assistant" should be "respondent defined." The one exception was that "visits to dentists or oral surgeons" were not to be included. Thus, for example, a reported visit to a chiropractor would have been excluded for 1969-81 and included for 1982 forward.

The first digit identifies time periods which can be identified in all years: Never (code 1), Less than 1 year (code 2), 1 year or more (code 3), 5 years or more (code 4), and unknown (code 9). The second and third digits identify periods specified for only a subgroup of years. Thus, for example, the longest time period coded varied across years: more than 3 years (for 1997-1998, code 310); 5 or more years (for 1970-1996 and 1999-2018, code 400); and more than 10 years (1969 and 2019 forward, code 402).