Analysis strategies for a community trial to reduce adolescent ATOD use: A comparison of random coefficient and ANOVA/ANCOVA models

Murray, David M.; Lee Van Horn, M.; Hawkins, J. David; Arthur, Michael W.

doi:10.1016/j.cct.2005.09.008

« Previous Next »Contemporary Clinical Trials
Volume 27, Issue 2 , Pages 188-206, April 2006

Analysis strategies for a community trial to reduce adolescent ATOD use: A comparison of random coefficient and ANOVA/ANCOVA models

David M. Murray
- The Ohio State University, School of Public Health, B222 West 10th Avenue, Columbus, OH 43210, USA
- Corresponding author. Tel.: +1 614 293 2928; fax: +1 614 293 3937.
M. Lee Van Horn
- Department of Psychology, University of South Carolina, Barnwell Hall, Columbia, South Carolina 29208, USA
- Tel.: +1 803 777 2612; fax: +1 803 777 9558.
J. David Hawkins
- Social Development Research Group, School of Social Work, University of Washington 9725 Third Avenue NE, Suite 401, Seattle, Washington 98115, USA
- Tel.: +1 206 543 7665; fax: +1 206 543 4507.
Michael W. Arthur
- Social Development Research Group, School of Social Work, University of Washington 9725 Third Avenue NE, Suite 401, Seattle, Washington 98115, USA
- Tel.: +1 206 685 3858; fax: +1 206 543 4507.

Received 24 September 2004; accepted 1 September 2005.

Abstract

The Community Youth Development Study (CYDS) will evaluate the Communities That Care (CTC) operating system for its effects on alcohol, tobacco, drug use, and other outcomes among adolescents resident in the 24 participating communities. The CYDS employs a combination of both cross-sectional and cohort designs. We use data from an earlier study that included the CYDS communities to estimate power for CYDS intervention effects given several analytic models that might be applied to the multiple baseline and follow-up surveys that define the CYDS cross-sectional design. We compare pre–post mixed-model ANCOVA models against random coefficients models, both in one- and two-stage versions. The two-stage pre–post mixed-model ANCOVA offers the best power for the primary outcomes and will provide adequate power for detection of modest but important intervention effects.

Keywords: Group-randomized trial, Power, Analytic methods