The 1987 Field Representative's Manual instructed interviewers to record, ""DK Chewing Tobacco" if the respondent reported they did not know what chewing tobacco was. The Manuals from 1992 forward mention that using chewing tobacco includes chewing the tobacco or just placing it in the mouth.

From 1998 forward, the survey text included mention of specific brands ("Have you used chewing tobacco (such as Redman, Levi Garrett, or Beechnut) at least 20 times in your entire life?'). For the earlier years, these same brands were mentioned in the variable CHEWEV, ever chewed tobacco, the variable preceding the question for CHEW20LIFE.