Why have the tobacco variables changed on the public use data files over the years?
The first supplemental questionnaire on “smoking habits” appeared on the 1965 NHIS. Smoking prevalence and theories of behavioral change have advanced since then. As the questions changed, the variables have also changed. A smoking section was added to the NHIS core as part of a major questionnaire redesign for the 1997 data collection year. Since then, the core smoking variables have remained relatively consistent, although additions are made for periodic tobacco use supplements.
