grouprar - Group Response Adaptive Randomization for Clinical Trials

Implements group response-adaptive randomization procedures, which include standard (non-group) response-adaptive randomization methods as special cases. The package also handles delayed and missing responses, which broadens its use in real-world trials. It offers functions for simulating a variety of response-adaptive randomization procedures, to help guide the choice of design for a clinical trial, including the doubly adaptive biased coin design and the multi-arm efficient randomized adaptive design (ERADE), k-arm optimal target allocations, group sequential monitoring, and a function that computes allocation probabilities for an ongoing trial. For details of the methods and algorithms, see the following references: Wei, L. J. (1979) <doi:10.1214/aos/1176344614>; Wei, L. J. and Durham, S. (1978) <doi:10.1080/01621459.1978.10480109>; Durham, S. D., Flournoy, N. and Li, W. (1998) <doi:10.2307/3315771>; Ivanova, A., Rosenberger, W. F., Durham, S. D. and Flournoy, N. (2000) <https://www.jstor.org/stable/25053121>; Bai, Z. D., Hu, F. and Shen, L. (2002) <doi:10.1006/jmva.2001.1987>; Ivanova, A. (2003) <doi:10.1007/s001840200220>; Hu, F. and Zhang, L. X. (2004) <doi:10.1214/aos/1079120137>; Hu, F. and Rosenberger, W. F. (2006, ISBN:978-0-471-65396-7); Zhang, L. X., Chan, W. S., Cheung, S. H. and Hu, F. (2007) <https://www.jstor.org/stable/26432528>; Zhang, L. and Rosenberger, W. F. (2006) <doi:10.1111/j.1541-0420.2005.00496.x>; Hu, F., Zhang, L. X., Cheung, S. H. and Chan, W. S. (2008) <doi:10.1002/cjs.5550360404>; Tymofyeyev, Y., Rosenberger, W. F. and Hu, F. (2007) <doi:10.1198/016214506000000906>; Hu, F., Zhang, L. X. and He, X. (2009) <doi:10.1214/08-AOS655>; Zhu, H. and Hu, F. (2010) <doi:10.1214/10-AOS796>; Zhai, G., Li, Y., Zhang, L. and Hu, F. (2024) <doi:10.1002/sim.10220>; Alkhnefr, N., Hu, F. and Zhai, G. (2025) <doi:10.1177/09622802251362644>.