Some methodologic issues in analyzing data from a randomized adolescent tobacco and alcohol use prevention trial.

Three issues concerning the design and analysis of randomized behavioral intervention studies are illustrated and discussed within the framework of a tobacco and alcohol prevention trial among migrant Latino adolescents. The first issue arises when subjects are randomized in clusters rather than individually. Because subject observations cannot be assumed to be independent, information pertaining to the degree of clustering must be reported, and analyses must take the clustering into account. The second issue concerns the impact of compliance to the intervention and the importance of measuring compliance in the experimental and attention-control groups. A compliance analysis should control for participant contact with study personnel. Investigators must consider ways of constructing a compliance measure that is common to both conditions. Third, because outcomes are measured repeatedly over time, we illustrate the importance of assessing the impact of missing-data patterns on outcomes and the extent to which the patterns may modify the treatment effect.

RCT Entities:   Population Interventions Outcomes