All baseline NCS respondents were asked if they ever smoked even occasionally. Those who responded affirmatively were asked retrospectively to report the age when they had their first smoke. Recency of smoking was also assessed, with respondents who reported smoking at all in the past year being defined “current” smokers and those with less recent smoking defined “past” smokers. In addition, a Tobacco Supplement, in which more detailed information about history of smoking was obtained, was administered to a representative sub-sample of 4414 Part II NCS respondents out of the total Part II sample of 5877. The Tobacco Supplement began with a screening question that asked respondent if they ever in their life smoked daily for a month or more. Lifetime daily smokers were also assessed for DSM-III-R nicotine dependence. Age of onset and recency of daily smoking and nicotine dependence were assessed using the same approach as in the assessment of lifetime use. The NCS-2 assessment repeated these questions for respondents who were not in the baseline tobacco supplement.
