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Journal of Obesity
Volume 2018, Article ID 8767315, 7 pages
Review Article

Trial Characteristics and Appropriateness of Statistical Methods Applied for Design and Analysis of Randomized School-Based Studies Addressing Weight-Related Issues: A Literature Review

1Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY, USA
2Department of Anesthesiology, Montefiore Medical Center, Bronx, NY, USA
3Department of Counseling, School, and Educational Psychology, Graduate School of Education, University at Buffalo-SUNY, Buffalo, NY, USA
4Department of Pediatrics, University of Verona, Verona, Italy
5Pennington Biomedical Research Center, Baton Rouge, LA, USA
6D. Samuel Gottesman Library, Albert Einstein College of Medicine, Bronx, NY, USA
7Department of Epidemiology and Biostatistics, School of Public Health, Indiana University-Bloomington, Bloomington, IN, USA

Correspondence should be addressed to Moonseong Heo;

Received 26 January 2018; Accepted 23 April 2018; Published 25 June 2018

Academic Editor: Chris I. Ardern

Copyright © 2018 Moonseong Heo et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Objective. To evaluate whether clustering effects, often quantified by the intracluster correlation coefficient (ICC), were appropriately accounted for in design and analysis of school-based trials. Methods. We searched PubMed and extracted variables concerning study characteristics, power analysis, ICC use for power analysis, applied statistical models, and the report of the ICC estimated from the observed data. Results. papers were identified, and papers were included for evaluation. Overall, only a minority (21.5%) of studies incorporated ICC values for power analysis, fewer studies (8.3%) reported the estimated ICC, and 68.6% of studies applied appropriate multilevel models. A greater proportion of studies applied the appropriate models during the past five years (2013–2017) compared to the prior years (74.1% versus 63.5%, ). Significantly associated with application of appropriate models were a larger number of schools (), a larger sample size (), longer follow-up (), and randomization at a cluster level () and so were studies that incorporated the ICC into power analysis () and reported the estimated ICC (). Conclusion. Although application of appropriate models has increased over the years, consideration of clustering effects in power analysis has been inadequate, as has report of estimated ICC. To increase rigor, future school-based trials should address these issues at both the design and analysis stages.