Volume 27, Issue 9
Research Article

Efficient generation of constrained block allocation sequences

Ibrahim Salama

School of Business, North Carolina Central University, 1801 Fayetteville St., Durham, NC 27707, U.S.A.

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Anastasia Ivanova

Corresponding Author

E-mail address: aivanova@bios.unc.edu

Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599‐7420, U.S.A.

Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599‐7420, U.S.A.Search for more papers by this author
Bahjat Qaqish

Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599‐7420, U.S.A.

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First published: 30 August 2007
Citations: 20

Abstract

Selection bias is a potential problem, especially in trials where blinding is not possible. Randomization with a constrained block of large size provides better protection from selection bias than using a sequence of blocks of small size with the same maximum imbalance. We propose an algorithm that efficiently generates constrained block allocation sequences, and we describe two clinical trials in which such a constrained randomization was used. Copyright © 2007 John Wiley & Sons, Ltd.

Number of times cited according to CrossRef: 20

  • Statistical properties of minimal sufficient balance and minimization as methods for controlling baseline covariate imbalance at the design stage of sequential clinical trials, Statistics in Medicine, 10.1002/sim.8552, 39, 19, (2506-2517), (2020).
  • Bias Control in Randomized Controlled Clinical Trials, Principles and Practice of Clinical Trials, 10.1007/978-3-319-52677-5, (1-20), (2019).
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  • Approaches to expanding the two‐arm biased coin randomization to unequal allocation while preserving the unconditional allocation ratio, Statistics in Medicine, 10.1002/sim.7290, 36, 16, (2483-2498), (2017).
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