The Hutchinson Smoking Prevention Project trial: Design and baseline characteristics

Introduction. This paper describes the experimental design and baseline cha racteristics of the Hutchinson Smoking Prevention Project (HSPP), a 15-year trial to determine to what extent a grade 3-12 school-based tobacco use pr evention intervention can deter tobacco use throughout and beyond high scho ol. Design. Trial design features include use of the school district as the uni t of randomization, inclusion of the school district's entire enrollment of 3rd graders, longterm follow-up of the entire original cohort, and sample size and evaluation methods that account for the group-randomization and in traclass correlation of endpoints within school districts, The theory-based intervention is teacher-led and includes grade 3-10 curriculum units, teac her training, grade 9-12 tobacco use cessation materials, and high school s taff newsletters. Results. Baseline data were collected on the trial cohort of 8388 children and their parents and on the 40 collaborating school districts and communit ies. A comparison of the distribution of baseline variables between experim ental conditions shows good balance. Conclusions. The HSPP trial's experimental design will provide a rigorous t est of the intervention. The balance in baseline variables between the expe rimental and control conditions will help provide assurance that the trial' s intervention effectiveness results, scheduled for publication in 2000, wi ll be unbiased. (C) 2000 American Health Foundation and Academic Press.