"Cross-sectional" stepped wedge designs always reduce the required sample size when there is no time effect

Affiliations

¹ Departments of Epidemiology and Biostatistics, Harvard T.H. Chan School of Public Health, 677 Hungtington Avenue, Boston, MA 02115, USA. Electronic address: stxzh@channing.harvard.edu.
² AbbVie Inc., Data and Statistical Sciences, 1 North Waukegan Road, North Chicago, IL 60064, USA.
³ Departments of Epidemiology and Biostatistics, Harvard T.H. Chan School of Public Health, 677 Hungtington Avenue, Boston, MA 02115, USA.

Comment

Xin Zhou et al. J Clin Epidemiol. 2017 Mar.

. 2017 Mar:83:108-109.

doi: 10.1016/j.jclinepi.2016.12.011. Epub 2017 Jan 16.

¹ Departments of Epidemiology and Biostatistics, Harvard T.H. Chan School of Public Health, 677 Hungtington Avenue, Boston, MA 02115, USA. Electronic address: stxzh@channing.harvard.edu.
² AbbVie Inc., Data and Statistical Sciences, 1 North Waukegan Road, North Chicago, IL 60064, USA.
³ Departments of Epidemiology and Biostatistics, Harvard T.H. Chan School of Public Health, 677 Hungtington Avenue, Boston, MA 02115, USA.

No abstract available

Comment on

Stepped wedge designs could reduce the required sample size in cluster randomized trials.
Woertman W, de Hoop E, Moerbeek M, Zuidema SU, Gerritsen DL, Teerenstra S. Woertman W, et al. J Clin Epidemiol. 2013 Jul;66(7):752-8. doi: 10.1016/j.jclinepi.2013.01.009. Epub 2013 Mar 22. J Clin Epidemiol. 2013. PMID: 23523551
The stepped wedge cluster randomized trial always requires fewer clusters but not always fewer measurements, that is, participants than a parallel cluster randomized trial in a cross-sectional design. In reply.
de Hoop E, Woertman W, Teerenstra S. de Hoop E, et al. J Clin Epidemiol. 2013 Dec;66(12):1428. doi: 10.1016/j.jclinepi.2013.07.008. Epub 2013 Sep 8. J Clin Epidemiol. 2013. PMID: 24021612 No abstract available.
The efficiency of stepped wedge vs. cluster randomized trials: stepped wedge studies do not always require a smaller sample size.
Hemming K, Girling A. Hemming K, et al. J Clin Epidemiol. 2013 Dec;66(12):1427-8. doi: 10.1016/j.jclinepi.2013.07.007. Epub 2013 Sep 10. J Clin Epidemiol. 2013. PMID: 24035495 No abstract available.

1. Woertman W, de Hoop E, Moerbeek M, Zuidema SU, Gerritsen DL, Teerenstra S. Stepped wedge designs could reduce the required sample size in cluster randomized trials. J Clin Epidemiol. 2013;66:752–8. - PubMed
1. Hemming K, Girling A. The efficiency of stepped wedge vs. cluster randomized trials: stepped wedge studies do not always require a smaller sample size. J Clin Epidemiol. 2013;66:1427–8. - PubMed
1. de Hoop E, Woertman W, Teerenstra S. The stepped wedge cluster randomized trial always requires fewer clusters but not always fewer measurements, that is, participants than a parallel cluster randomized trial in a cross-sectional design. In Reply J Clin Epidemiol. 2013;66:1428. - PubMed
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