Open Access

Erratum to: Sample size calculations for cluster randomised controlled trials with a fixed number of clusters

  • Karla Hemming1Email author,
  • Alan J Girling1,
  • Alice J Sitch1,
  • Jennifer Marsh1 and
  • Richard J Lilford1
BMC Medical Research MethodologyBMC series – open, inclusive and trusted201717:8

DOI: 10.1186/s12874-017-0292-x

Published: 19 January 2017

The original article was published in BMC Medical Research Methodology 2011 11:102

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:
$$ m=\frac{\left(1-\rho \right){n}_{I\ }}{k-{n}_I\left(c{v}^2+1\right)} $$
The correct version of equation 16 is:
$$ m=\frac{\left(1-\rho \right){n}_{I\ }}{k-{n}_I\left(c{v}^2+1\right)\rho } $$

Notes

Declarations

Open AccessThis 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.

Authors’ Affiliations

(1)
Department of Public Health, Epidemiology and Biostatistics, University of Birmingham

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.View ArticlePubMedPubMed CentralGoogle Scholar

Copyright

© The Author(s). 2017

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