powerfamily: Finding extended power-family group-sequential designs

In OptGS: Near-Optimal and Balanced Group-Sequential Designs for Clinical Trials with Continuous Outcomes

Description

powerfamily is used to find a one-sided extended power-family group-sequential design

Usage

powerfamily(futility = 0, efficacy = 0, delta0 = 0, delta1 = 1/3,
    J = 2, sigma = 1, sd.known = TRUE, alpha = 0.05, power = 0.9)

Arguments

futility	shape parameter for futility boundaries (default: 0)
efficacy	shape parameter for efficacy boundaries (default: 0)
delta0	mean difference in treatment effect under the null hypothesis (default: 0)
delta1	clinically relevant difference used to power the trial (default: 1/3)
J	number of stages in the trial (default: 2)
sigma	assumed standard deviation of treatment responses (default: 1)
sd.known	logical value indicating if sigma will be treated as known; if FALSE, a quantile substitution method will be used to modify the stopping boundaries (default TRUE)
alpha	one-sided type-I error rate required (default: 0.05)
power	power required (default: 0.9)

Details

powerfamily uses the extended power-family of group-sequential tests. A description of the extended power-family is provided in Wason (2012).

Value

groupsize	the number of patients required per arm, per stage
futility	the futility boundaries for the design
efficacy	the efficacy boundaries for the design
ess	the expected sample size at the delta0; the expected sample size at the delta1; and the maximum expected sample size
typeIerror	the actual type-I error rate of the design
power	the actual power of the design

References

Wason, J.M.S. OptGS: an R package for finding near-optimal group-sequential designs. Journal of Statistical Software, 66(2), 1-13. http://www.jstatsoft.org/v66/i02/

Examples

##Find a three-stage design that has shape parameters -0.5 and 0.5.
threestagedesign=powerfamily(J=3,futility=-0.5,efficacy=0.5) 
plot(threestagedesign)

OptGS documentation built on May 2, 2019, 8:58 a.m.