Sample size calculations for cluster randomised controlled trials with a fixed number of clusters
نویسندگان
چکیده
منابع مشابه
Erratum to: Sample size calculations for cluster randomised controlled trials with a fixed number of clusters
BACKGROUND Cluster randomised controlled trials (CRCTs) are frequently used in health service evaluation. Assuming an average cluster size, required sample sizes are readily computed for both binary and continuous outcomes, by estimating a design effect or inflation factor. However, where the number of clusters are fixed in advance, but where it is possible to increase the number of individuals...
متن کاملSample size in cluster randomised trials with unequal clusters
Objectives The aim of RCTs is to obtain unbiased estimates of treatment effects to answer the question of interest. In a cluster randomised trial (CRT), maximum statistical efficiency is obtained if an equal sized sample from each cluster is selected. In practice, the ability to achieve equal cluster size is an exception rather than the norm. Two CRTs run by the Leeds CTRU; TRACS (Training Care...
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Most informed consent documents for randomized controlled trials implicitly or explicitly promise the prospective participant that the trial has a reasonable chance of answering a medically important question. The medical literature, however, is replete with descriptions of trials that provided equivocal answers to the questions they addressed. Papers describing the results of such studies may ...
متن کاملRandomised Controlled Trials (RCTs) – Sample Size: The Magic Number?
Correspondence to: Y H Chan Tel: (65) 6317 2121 Fax: (65) 6317 2122 Email: chanyh@ cteru.gov.sg INTRODUCTION A common question posed to a biostatistician from a medical researcher is “How many subjects do I need to obtain a significant result for my study?”. That magic number! In the manufacturing industry, it is permitted to test thousands of components in order to derive a conclusive result b...
متن کاملA review of methodology for sample size calculations in cluster randomised trials
Methods A systematic review is being conducted of sample size methodology for cluster randomised trials. The sources for the search include electronic databases PubMed and Web of Science, key text books on cluster randomised trials and discussions with experts in the field. The search strategy involves a compliment of Medical Subject Headings and free text terms to aid a comprehensive search. T...
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ژورنال
عنوان ژورنال: BMC Medical Research Methodology
سال: 2011
ISSN: 1471-2288
DOI: 10.1186/1471-2288-11-102