Journal / Book Title
This article compares four mixed-model analyses valid for group-randomized trials (GRTs) involving a nested cohort design with a single pretest and a single posttest, the most common design used in GRTs. This study makes estimates of intraclass correlations (ICCs) available to investigators planning GRTs with alcohol, tobacco, and other drug measures as the outcomes of interest. It also provides formulae demonstrating the potential benefits to the standard error of the intervention effect of both adjustments for fixed and time-varying covariates, as well as correlations over time. These estimates will allow other researchers using these variables to plan their studies by performing a priori power analyses for any of four common analytic options.
MSU Digital Commons Citation
Janega, Jessica B.; Murray, David M.; Varnell, Sherri P.; Blitstein, Jonathan L.; Birnbaum, Amanda; and Lytle, Leslie A., "Assessing the most powerful analysis method for school-based intervention studies" (2004). Department of Public Health Scholarship and Creative Works. 70.
Janega, Jessica B., David M. Murray, Sherri P. Varnell, Jonathan L. Blitstein, Amanda S. Birnbaum, and Leslie A. Lytle. "Assessing the most powerful analysis method for school-based intervention studies with alcohol, tobacco, and other drug outcomes." Addictive behaviors 29, no. 3 (2004): 595-606.
Applied Behavior Analysis Commons, Clinical Epidemiology Commons, Community Health and Preventive Medicine Commons, Epidemiology Commons, Health Services Administration Commons, Health Services Research Commons, International Public Health Commons, Medical Sciences Commons, Other Medicine and Health Sciences Commons, Other Public Health Commons, Other Social and Behavioral Sciences Commons, Public Health Education and Promotion Commons, Rehabilitation and Therapy Commons