One Cluster per Condition Is Not a Valid Design in Cluster-Randomized Trials. Comment on Wang et al. The Effect of Different Physical Exercise Programs on Physical Fitness among Preschool Children: A Cluster-Randomized Controlled Trial. Int. J. Environ. Res. Public Health 2023, 20, 4254

Int J Environ Res Public Health. 2023 Aug 29;20(17):6673. doi: 10.3390/ijerph20176673.

¹ Department of Epidemiology and Biostatistics, Indiana University School of Public Health-Bloomington, Bloomington, IN 47405, USA.
² Department of Health and Wellness Design, Indiana University School of Public Health-Bloomington, Bloomington, IN 47405, USA.
³ Department of Biostatistics, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
⁴ Arkansas Children's Research Institute, Little Rock, AR 72202, USA.

Abstract

Wang et al. [...].