In 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.

RAHUL BHATTACHARYA

Statistics

U BANDYOPADHYAY

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

On an ethical cum optimal adaptive allocation design

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. © 2018, © 2018 Taylor & Francis Group, LLC.

Communications in Statistics - Theory and Methods

A multi-treatment two stage adaptive allocation for survival outcomes

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. © 2018, © 2018 Grace Scientific Publishing, LLC.

Journal of Statistical Theory and Practice

A two-stage adaptive allocation design for survival outcome with informative censoring

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. © 2014, Springer-Verlag Berlin Heidelberg.

Statistical Methods and Applications

A randomized two stage allocation for continuous response clinical trials

In this paper, given an arbitrary fixed target sample size, we describe a sequential allocation scheme for comparing two competing treatments in clinical trials. The proposed scheme is a compromise between ethical and optimum allocations. Using some specific probability models, we have shown that, for estimating the risk difference (RD) between two treatment effects, the scheme provides smaller variance than that provided by the corresponding fixed sample size equal allocation sampling scheme. © 2004 Elsevier B.V. All rights reserved.

Journal of Statistical Planning and Inference

An optimal sequential procedure in ethical allocation

Adaptive designs are often used in clinical trials to force balance in sequential allocation of patients between two or more competitive treatments. Sometimes, from ethical considerations, the goal may be to allocate a larger number of patients to the better treatment in the course of the trial. In the present paper we consider patients who are heterogeneous with respect to some prognostic factors and assume that the response from each patient is a continuous variable. We consider a normal linear model and provide an allocation design with due attention to the prognostic factors. The loss of efficiency incurred by using a balanced design is also indicated. Issues of inference based on adaptive allocation are also discussed. Finally a guideline is provided for the appropriate choice of the design parameters. © 2001 Biometrika Trust.

Journal	Statistics
Publisher	TAYLOR & FRANCIS LTD
ISSN	0233-1888
Open Access	No