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Estimation of Treatment Difference and Standard Deviation with Blinded Data in Clinical Trials
Author(s) -
Chen Michael,
Kianifard Farid
Publication year - 2003
Publication title -
biometrical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.108
H-Index - 63
eISSN - 1521-4036
pISSN - 0323-3847
DOI - 10.1002/bimj.200390000
Subject(s) - standard deviation , sample size determination , standard error , statistics , clinical trial , mean difference , computer science , randomized controlled trial , mathematics , medicine , confidence interval , surgery , pathology
In an ongoing clinical trial and while the randomized treatment codes remain blinded, it is often desirable to estimate the treatment difference and standard deviation for a normally‐distributed response variable. This is particularly useful for estimating the sample size for future trials or for adjusting the sample size for the ongoing trial. We describe the limitations of an available EM algorithm‐based procedure to reestimate the standard deviation without unblinding the codes for the two treatments. We introduce a new procedure and propose a clinical trial design for estimating both the treatment difference and standard deviation without unblinding. The performance of the proposed procedure is evaluated in a simulation study.