Hemming et al. BMC Medical Research Methodology (2017) 17:8 DOI 10.1186/s12874-017-0292-x
ERRATUM
Open Access
Erratum to: Sample size calculations for cluster randomised controlled trials with a fixed number of clusters Karla Hemming*, Alan J Girling, Alice J Sitch, Jennifer Marsh and Richard J Lilford Erratum After publication of the original article [1], it came to the authors’ attention that there was a typing error in equation 16. There should be a rho on the denominator of this equation. The published version of equation 16 is: m¼
ð1−ρÞnI k−nI ðcv2 þ 1Þ
The correct version of equation 16 is: m¼
ð1−ρÞnI k−nI ðcv2 þ 1Þρ
References 1. Hemming K, Girling AJ, Sitch AJ, Marsh J, Lilford RJ. Sample size calculations for cluster randomised controlled trials with a fixed number of clusters. BMC Med Res Methodol. 2011;11:102. doi:10.1186/1471-2288-11-102.
* Correspondence: [email protected] Department of Public Health, Epidemiology and Biostatistics, University of Birmingham, Birmingham, UK © The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
ERRATUM
Open Access
Erratum to: Sample size calculations for cluster randomised controlled trials with a fixed number of clusters Karla Hemming*, Alan J Girling, Alice J Sitch, Jennifer Marsh and Richard J Lilford Erratum After publication of the original article [1], it came to the authors’ attention that there was a typing error in equation 16. There should be a rho on the denominator of this equation. The published version of equation 16 is: m¼
ð1−ρÞnI k−nI ðcv2 þ 1Þ
The correct version of equation 16 is: m¼
ð1−ρÞnI k−nI ðcv2 þ 1Þρ
References 1. Hemming K, Girling AJ, Sitch AJ, Marsh J, Lilford RJ. Sample size calculations for cluster randomised controlled trials with a fixed number of clusters. BMC Med Res Methodol. 2011;11:102. doi:10.1186/1471-2288-11-102.
* Correspondence: [email protected] Department of Public Health, Epidemiology and Biostatistics, University of Birmingham, Birmingham, UK © The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
