In 1992, but not in 1998, respondents could have answered, "I think so." In IPUMS NHIS, this response is considered to be "yes" and is recoded accordingly.

If respondents reported an oral cancer exam fitting the description in the question, the 1992 Field Representative's Manual instructed interviewers to, "Accept this as a 'Yes' if the doctor or dentist called it an oral cancer exam."

In the 1992 Manual, the stated purpose of these questions was to, "...determine the public's knowledge, attitudes, and practices in regard to certain cancer screening tests and examinations." The Manual continues with, "The results of these data will be used to assess barriers and determinants of behavior in relation to cancer screening tests, and will be used to target education programs that emphasize the knowledge and behaviors needed."