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grouprar 0.2.0

New features

• Multi-arm efficient randomized adaptive design (ERADE): the DBCD-family designs gain allocation = "ERADE" and erade.alpha (Hu, Zhang and He, 2009, for two arms; Alkhnefr, Hu and Zhai, 2025, for k arms).
• k-arm optimal target allocations with a lower bound lower.bound on each proportion: "OptimalNeyman" and "OptimalRSIHR" for binary responses (Tymofyeyev, Rosenberger and Hu, 2007) and "OptimalNeyman" for continuous responses. "ZR" now works for any number of arms and, for two arms, follows rule (7) of Zhang and Rosenberger (2006).
• Group sequential monitoring for two-arm designs (DBCD_Bin(), DBCD_Cont(), Group.DBCD_Bin(), Group.DBCD_Cont()) through the new monitor argument, sqMonitor() and sqBoundary(), with O’Brien-Fleming, Pocock and linear alpha spending (Zhu and Hu, 2010). Results include the stopping probability at each look and the expected sample size.
• nextAlloc() computes the allocation probabilities (and optionally the assignments) of the next patient or group in an ongoing trial.
• All designs gain test.fun (user-supplied test returning a p-value), typeI (also estimates the type I error under the null) and seed.
• Results are objects of class "grouprar" with print() and summary() methods. They now include the allocation sequence of every simulated trial (data: allocation) and the SD of the allocation proportion of every arm (sd of propotion, previously arm 1 only). Delayed designs also report the trial duration and the enrollment duration.

Bug fixes

• The Hu and Zhang (2004) allocation function behind all DBCD designs now normalizes each arm jointly against all k arms. Previously each arm was compared with the pooled remaining arms, which agrees with Hu and Zhang (2004) only for two arms. Results for two-arm designs are unchanged. Thanks to Stina Zetterstrom, David S. Robertson and Sofía S. Villar for the report (StinaZet/RAR-software-bugs#7).
• dyldDBCD_Bin() updated its estimates with the responses of the wrong patients and ignored late responses of the initial patients. It also failed for more than two arms.
• Bai.Hu.Shen.Urn() updated the urn with the true success rates. It now implements the proposed design of Bai, Hu and Shen (2002), which uses the estimated success rates.
• dyldDBCD_Cont() ignored the r argument, failed for more than two arms, did not mark missing responses as unobserved, and did not update the allocation when a response of one of the initial patients arrived.
• dyldDBCD_Bin() and dyldDBCD_Cont() now recompute the allocation probability for every patient with the current allocation proportions (previously only when a new response arrived).
• Group.dyldDBCD_Bin() and Group.dyldDBCD_Cont() drew an extra group when the group sizes added up exactly to ssn.
• Group.dyldDBCD_Bin() used the wrong column of the response time matrix, so response times did not depend on the observed response as documented.
• DBCD_Bin() ignored mRate, and Group.DBCD_Cont() failed when mRate was set.
• With missing responses, the allocation proportions used by the allocation function now count all enrolled patients, as in Section 2.3 of Zhai et al. (2024). Group.DBCD_Bin() and Group.DBCD_Cont() previously counted only patients with observed responses. The reported allocation proportions (propotion) of all designs with mRate also count all enrolled patients now; the failure rate and the test still use the observed responses only.
• DBCD_Bin() and DBCD_Cont() now use the chi-squared test for more than two arms, and the chi-squared test for continuous responses uses the sample variance of each arm.
• The tests no longer fail for two arms (PolyaUrn(), WeiUrn()), for arms without patients, or for arms without variability. For binary responses with more than two arms, arms without variability no longer make the test NA: the Wald test then uses the adjusted variances of Agresti and Caffo (2000).
• GDLRule() returns one failure rate per simulation, and GDLRule(), DLRule() and BirthDeathUrn() no longer fail when aK or Y0 are not whole numbers (balls are drawn in proportion to the positive part of the urn).
• rspT.dist = "uniform" was rejected because of a typo.
• Allocation proportions are no longer misaligned when an arm has no patients.
• Equal allocation is used while the target cannot be estimated (e.g. fewer than two responses in an arm of a continuous design).
• RPWRule() stops with an error for k != 2, the DBCD-family designs check that n0 >= k and ssn > n0, and the group designs check that gsize.param > 0 (a rate of 0 made the initial phase loop forever). All designs check k >= 2, Y0, aK and the length of rspT.param.

Documentation

• Corrected return values, argument descriptions, references and examples in all help pages. Added a citation file.

Other changes

• Removed the unused ggplot2, gridExtra, methods and tidyr imports, and the dependency on stringr, whose current version needs R >= 4.1.
• Added unit tests and a GitHub Actions workflow for R CMD check.

These binaries (installable software) and packages are in development.
They may not be fully stable and should be used with caution. We make no claims about them.
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