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BMC Medical Research Methodology
Published in: BMC Medical Research Methodology 1/2004

Open Access 01-12-2004 | Research article

Intracluster correlation coefficients in cluster randomized trials: empirical insights into how should they be reported

Authors: Marion K Campbell, Jeremy M Grimshaw, Diana R Elbourne

Published in: BMC Medical Research Methodology | Issue 1/2004

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Abstract

Background

Increasingly, researchers are recognizing that there are many situations where the use of a cluster randomized trial may be more appropriate than an individually randomized trial. Similarly, the need for appropriate standards of reporting of cluster trials is more widely acknowledged.

Methods

In this paper, we describe the results of a survey to inform the appropriate reporting of the intracluster correlation coefficient (ICC) – the statistical measure of the clustering effect associated with a cluster randomized trial.

Results

We identified three dimensions that should be considered when reporting an ICC – a description of the dataset (including characteristics of the outcome and the intervention), information on how the ICC was calculated, and information on the precision of the ICC.

Conclusions

This paper demonstrates the development of a framework for the reporting of ICCs. If adopted into routine practice, it has the potential to facilitate the interpretation of the cluster trial being reported and should help the development of new trials in the area.
Appendix
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Metadata
Title
Intracluster correlation coefficients in cluster randomized trials: empirical insights into how should they be reported
Authors
Marion K Campbell
Jeremy M Grimshaw
Diana R Elbourne
Publication date
01-12-2004
Publisher
BioMed Central
Published in
BMC Medical Research Methodology / Issue 1/2004
Electronic ISSN: 1471-2288
DOI
https://doi.org/10.1186/1471-2288-4-9

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