Cardiff University | Prifysgol Caerdydd ORCA
Online Research @ Cardiff 
WelshClear Cookie - decide language by browser settings

Cluster size variability and imbalance in cluster randomized controlled trials

Carter, Ben Richard 2010. Cluster size variability and imbalance in cluster randomized controlled trials. Statistics in Medicine 29 (29) , pp. 2984-2993. 10.1002/sim.4050

Full text not available from this repository.


Cluster randomized controlled trials are increasingly used to evaluate medical interventions. Research has found that cluster size variability leads to a reduction in the overall effective sample size. Although reporting standards of cluster trials have started to evolve, a far greater degree of transparency is needed to ensure that robust evidence is presented. The use of the numbers of patients recruited to summarize recruitment rate should be avoided in favour of an improved metric that illustrates cumulative power and accounts for cluster variability. Data from four trials is included to show the link between cluster size variability and imbalance. Furthermore, using simulations it is demonstrated that by randomising using a two block randomization strategy and weighting the second by cluster size recruitment, chance imbalance can be minimized.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Medicine
Subjects: R Medicine > R Medicine (General)
Uncontrolled Keywords: cluster randomized controlled trials; cluster size variability; imbalance; intra-cluster correlation; optimization randomization algorithm; power
Publisher: John Wiley & Sons
ISSN: 0277-6715
Last Modified: 04 Jun 2017 03:34

Citation Data

Cited 16 times in Scopus. View in Scopus. Powered By Scopus® Data

Actions (repository staff only)

Edit Item Edit Item