chenPar {randomizeR}

Representing Chen's Design

Description

Represents the randomization procedure Chen's Design.

Usage

chenPar(N, mti = N, p = 0.5, groups = LETTERS[1:2])

Arguments

N

integer for the total sample size of the trial.

mti

maximum tolerated imbalance in patient numbers during the trial.

p

success probability of the biased coin (e.g. in Efron's Biased Coin Design).

groups

character vector of labels for the different treatments.

Details

Flip a biased coin with probability p in favor of the treatment which is allocated less frequently as long as the difference in group sizes does not exceed the mti. If the mti is reached a deterministic allocation is done, so that the difference in group sizes is reduced. If both treatments have been assigned equally often a fair coin is tossed.

Value

S4 object of the class chenPar.

References

Chen Yung-Pin (1999) Biased coin design with imbalance tolerance. Comm. in Stat., 15, 953-975.

See Also

Other randomization procedures: abcdPar, bbcdPar, bsdPar, crPar, createParam(), ebcPar, gbcdPar, hadaPar, mpPar, pbrPar, rarPar, rpbrPar, rtbdPar, tbdPar, udPar