 Missing responses in adaptive allocation designAtanu Biswas and J.N.K. Rao Statistics & Probability Letters, 2004, vol. 70, issue 1, 59-70 Abstract: Adaptive allocation designs are used in phase III clinical trials. Sometimes, from ethical considerations, the goal may be to skew the allocation pattern in favour of the better treatment. Bandyopadhyay and Biswas (Biometrika 88 (2001) 409) studied such allocation designs for two competing treatments, when the patients heterogeneous with respect to some prognostic factors and the response from each patient was continuous. In the present paper, we extend the work to the case of missing responses. Under missing at random assumption, we impute for the missing data at every stage depending on the data available at that point in time. We obtain the conditional and unconditional allocation probabilities and the standard error of the estimated treatment difference at each stage. Through simulation, we show that imputation for missing responses under this adaptive design set-up has a clear gain over the method that uses only complete data. The gain is in the sense that the power is larger and the standard error of the estimated treatment difference is smaller. Keywords: Efficiency; Limiting; proportion; of; allocation; Linear; regression; imputation; Missing; at; random; Probit; link (search for similar items in EconPapers) Downloads: (external link) Related works: Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text Persistent link: https://EconPapers.repec.org/RePEc:eee:stapro:v:70:y:2004:i:1:p:59-70 Ordering information: This journal article can be ordered from Access Statistics for this article Statistics & Probability Letters is currently edited by Somnath Datta and Hira L. Koul More articles in Statistics & Probability Letters from Elsevier |
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