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dc.contributor.authorGrayling, Michaelen
dc.contributor.authorMander, Adrianen
dc.contributor.authorWason, Jamesen
dc.date.accessioned2018-11-26T14:29:09Z
dc.date.available2018-11-26T14:29:09Z
dc.date.issued2018-09-03en
dc.identifier.issn1521-4036
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/285980
dc.description.abstractThe ability to accurately estimate the sample size required by a stepped-wedge (SW) cluster randomized trial (CRT) routinely depends upon the specification of several nuisance parameters. If these parameters are misspecified, the trial could be over-powered, leading to increased cost, or under-powered, enhancing the likelihood of a false negative. We address this issue here for cross-sectional SW-CRTs, analyzed with a particular linear mixed model, by proposing methods for blinded and unblinded sample size re-estimation (SSRE). First, blinded estimators for the variance parameters of a SW-CRT analyzed using the Hussey and Hughes model are derived. Following this, procedures for blinded and unblinded SSRE after any time period in a SW-CRT are detailed. The performance of these procedures is then examined and contrasted using two example trial design scenarios. We find that if the two key variance parameters were under-specified by 50%, the SSRE procedures were able to increase power over the conventional SW-CRT design by up to 41%, resulting in an empirical power above the desired level. Thus, though there are practical issues to consider, the performance of the procedures means researchers should consider incorporating SSRE in to future SW-CRTs.
dc.publisherWiley-Blackwell
dc.rightsAttribution 4.0 International*
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/*
dc.subjectblindeden
dc.subjectcluster randomized trialen
dc.subjectinternal piloten
dc.subjectsample size re-estimationen
dc.subjectstepped-wedgeen
dc.titleBlinded and unblinded sample size re-estimation procedures for stepped-wedge cluster randomized trialsen
dc.typeArticle
prism.endingPage916
prism.issueIdentifier5en
prism.publicationDate2018en
prism.publicationNameBiometrical Journalen
prism.startingPage903
prism.volume60en
dc.identifier.doi10.17863/CAM.33304
dcterms.dateAccepted2018-06-27en
rioxxterms.versionofrecord10.1002/bimj.201700125en
rioxxterms.versionVoR*
rioxxterms.licenseref.urihttp://creativecommons.org/licenses/by/4.0/en
rioxxterms.licenseref.startdate2018-09-03en
dc.contributor.orcidGrayling, Michael [0000-0002-0680-6668]
dc.contributor.orcidMander, Adrian [0000-0002-0742-9040]
dc.contributor.orcidWason, James [0000-0002-4691-126X]
rioxxterms.typeJournal Article/Reviewen
pubs.funder-project-idWellcome Trust (099770/Z/12/Z)
pubs.funder-project-idMRC (unknown)
cam.issuedOnline2018-08-03en
dc.identifier.urlhttps://onlinelibrary.wiley.com/doi/full/10.1002/bimj.201700125en
cam.orpheus.successThu Jan 30 10:53:54 GMT 2020 - The item has an open VoR version.*
rioxxterms.freetoread.startdate2100-01-01


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Attribution 4.0 International
Except where otherwise noted, this item's licence is described as Attribution 4.0 International