The present analysis utilized a male sample selected from the Harvard classes of 1942–1944 (Vaillant, 1979). The 268 participants had a mean birth year of 1921 (SD=2 years) and were selected as sophomores from 1938–1942 (Vaillant, 1996). Participants were followed by annual or biennial questionnaires, which included questions regarding smoking behavior, from age 21 (Vaillant, 2003) through 2003. Thirty-six participants missing tobacco data on 17 or more of the 22 assessments were excluded (95th percentile or higher for amount of missing data).
