stage_1_evaluation {GSED}

Stage 1-evaluation step of GSED

Description

stage_1_evaluation is used to evaluate the efficacy of the subgroup selected at the end of the first stage of GSED.

Usage

stage_1_evaluation(keep, Z_1j, f, u)

Arguments

keep

Vector containing the indices of the subgroups selected at stage 1.

Z_1j

Vector containing the Z-statistics (standard normal under H0) for each subgroup. Must be of length N_subsets.

f

Vector containing the prevalence rates of each subgroup.

u

Vector containing the upper boundaries for stagewise decisions.

Value

A list is returned, consisting of:

stage

Integer containing the current step. Value is 1 by default, or -1 if the trial stops earlier for efficacy after this evaluation step.

S

Vector containing the indices of the subgroups selected at stage 1 (=keep).

Author(s)

Marie-Karelle Riviere-Jourdan [e-mail]

References

Baldur P. Magnusson and Bruce W. Turnbull. Group sequential enrichment design incorporating subgroup selection. Statistics in Medicine, 2013. <doi:10.1002/sim.5738>

Examples

stage_1_evaluation(keep=c(2,3), Z_1j=c(-0.49,1.07,1.44), f=c(0.6,0.2,0.2), u=c(2.7625,2.5204))