Author Contributions: Dr Sargent had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Sargent, Heatherton.
Acquisition of data: Sargent.
Analysis and interpretation of data: Sargent.
Drafting of the manuscript: Sargent.
Critical revision of the manuscript for important intellectual content: Sargent, Heatherton.
Statistical analysis: Sargent.
Obtained funding: Sargent, Heatherton.
Administrative, technical, or material support: Heatherton.
Financial Disclosures: None reported.
Funding/Support: This work was supported by National Cancer Institute grant CA-77026 and the American Legacy Foundation.
Role of the Sponsors: The sponsors had no role in the design and conduct of the study; in the collection, management, analysis, and interpretation of the data; or in the preparation, review, or approval of the manuscript.
Additional Contributions: For the adolescent smoking analyses, Lloyd D. Johnston, PhD; Patrick O’Malley, PhD; Patricia Berglund, MBA; and Timothy Perry, MS, University of Michigan Institute for Social Research, obtained the information on sample size for eighth graders, calculated the 95% CIs, and conducted the linear test for trend. None of these individuals received compensation for their role in the study.