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Journal ArticleDOI

On an ethical cum optimal adaptive allocation design

30 Nov 2007-Statistics (Taylor & Francis)-Vol. 41, Iss: 6, pp 471-483

AbstractIn the present work, we formulate a two-treatment single period two-stage adaptive allocation design for achieving larger allocation proportion to the better treatment arm in the course of the trial with increased precision of the parameter estimator. We examine some properties of the proposed rule and compare it with some of the existing allocation rules and report substantial gain in efficiency with a considerably larger number of allocations to the better treatment even for moderate sample sizes.

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Citations
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Journal ArticleDOI
TL;DR: A randomized two treatment allocation design, conducted in two stages, is proposed for a class of continuous response trials and relevant properties of the proposed allocation design are investigated and compared with suitable competitors.
Abstract: A randomized two treatment allocation design, conducted in two stages, is proposed for a class of continuous response trials. Patients are assigned to each treatment in equal numbers in the first stage and p value of a test of equality of treatment effects based on these data is used to determine the assignment probability of second stage patients. Relevant properties of the proposed allocation design are investigated and compared with suitable competitors.

4 citations

Journal ArticleDOI
TL;DR: A class of adaptive designs is formulated in two stages for clinical trials to favour the better performing treatment for further allocation in an efficient way and compare with the existing allocation designs.
Abstract: A class of adaptive designs is formulated in two stages for clinical trials to favour the better performing treatment for further allocation in an efficient way. The first stage of the allocation consists in randomizing subjects to each treatment arm with equal probability and performing a test of equality of treatment effects. The resulting p value and the available estimate of a treatment difference measure is used to assign the incoming second stage subjects. Considering binary and normal responses, several exact and asymptotic properties of the proposed allocation are thoroughly examined and compared with the existing allocation designs.

1 citations


Cites background from "On an ethical cum optimal adaptive ..."

  • ...Bandyopadhyay and Bhattacharya (2006) and Bandyopadhyay and Bhattacharya (2007) identified these issues and incorporating randomization in a convenient way, developed an ethical allocation after sequential determination of the first stage sampling allocation fraction....

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Journal ArticleDOI
Abstract: A multi-treatment two stage adaptive allocation design is developed for survival responses. Assuming noninformative random censoring, asymptotic p values of relevant tests of equality of treatment effects are used to derive the assignment probability of incoming second stage subjects. Several ethical and inferential criteria of the design are studied, and are compared with those of an existing competitor. Applicability and performance of the proposed design are also illustrated using a data arising from a real clinical trial.

1 citations

Journal ArticleDOI
Abstract: An adaptive two-stage allocation design is developed for survival responses subject to independent informative censoring. The asymptotic p value of a score test related to a hypothesis of treatment effectiveness is used to set the assignment probability of the second stage. Several characteristics of the design and the follow-up inference are studied, both numerically and theoretically, and are compared with those of an existing competitor. Applicability of the proposed design is also illustrated through a real data.

1 citations


References
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Journal ArticleDOI
01 May 1984

3,042 citations

Book
23 Sep 2014

2,928 citations

Journal ArticleDOI
TL;DR: Investigation of the conduct of a clinical trial where the “Play the Winner Rule” (PWR) is used to assign patients to the different therapies shows that over a wide range of situations this rule leads to near optimum results when used in a two-stage manner.
Abstract: Consider a clinical trial to compare two treatments where response is dichotomous and patients enter the trial sequentially. This paper investigates the conduct of such a trial where the “Play the Winner Rule” (PWR) is used to assign patients to the different therapies. The implementation of the PWR in a clinical trial tends to place more patients on the better treatment. Both theoretical and numerical investigations show that over a wide range of situations this rule leads to near optimum results when used in a two-stage manner. Furthermore, these results are insensitive to optimum sample size requirements.

422 citations

Journal ArticleDOI
Abstract: In a sequential medical trial, a simple randomized treatment assignment rule is proposed and analyzed. On the average this rule assigns more patients to the better treatment, and it is applicable to the case where patients have delayed responses to treatments. This new assignment rule is studied for both a fixed sample size and an inverse stopping rule.

422 citations


Additional excerpts

  • ...[2] for randomized-play-the-winner rule and ref....

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Book
11 Jul 2002
Abstract: Preface Randomization and the Clinical Trial Issues in the Design of Clinical Trials Randomization for Balancing Treatment Assignments Balancing on Known Covariates The Effects of Unobserved Covariates Selection Bias Randomization as a Basis for Inference Inference for Stratified, Blocked, and Covariate-Adjusted Analyses Randomization in Practice Response-Adaptive Randomization Inference for Response-Adaptive Rondomization Response-Adaptive Randomization in Practice Some Useful results in Large Sample Theory Large Sample Inference for Complete and Restricted Randomization Large sample Inference for Response-Adaptive Randomization Author Index Subject Index

367 citations