vector with the cumulative information fraction (default: (1:K)/K)
Imax
maximum information number (default: NULL)
SF
spending function (for details see below)
phi
parameter of spending function when SF=3 or 4 (See below)
alpha
alpha (type I error rate)
delta
effect size (alternative)(default: NULL)
pow
power (default: NULL)
compute.alab
specify if alpha-absorbing parameter values should be calculated (default: TRUE)
compute.als
specify if alpha-values ”spent” at every stage should be calculated (default: TRUE)
Details
The user has to specify either Imax or delta and pow.
If all three items are specified, the pre-defined maximum information number is newly calculated from the information for delta and power, and Imax is overwritten.
SF defines the spending function.
SF =
1 O'Brien and Fleming type spending function of Lan and DeMets (1983)
SF =
2 Pocock type spending function of Lan and DeMets (1983)
SF =
3 Power family (c_α* t^φ); phi must be greater than 0
SF =
4 Hwang-Shih-DeCani family; (1-e^{-φ t})/(1-e^{-φ}), where phi cannot be 0
Value
plan.GST returns an object of the classGSTobj.
An object of class GSTobj is a list containing the following
components:
K
number of stages
a
lower critical bounds of group sequential design (are currently always set to -8)
b
upper critical bounds of group sequential design
t
vector with cumulative information fraction
al
alpha (type I error)
SF
spending function
phi
parameter of spending function when SF=3 or 4 (See below)
Brannath, W, Mehta, CR, Posch, M (2008) ”Exact confidence bounds following
adaptive group sequential tests”, Biometrics accepted.
See Also
GSTobj, print.GSTobj, plot.GSTobj
Examples
##The following plans an O'Brien and Flaming group sequential design (GSD)
##with 4 stages and equally spaced looks.
pT <- plan.GST(K=4, SF=1, phi=0, alpha=0.025, delta=6, pow=0.8, compute.alab=TRUE, compute.als=TRUE)
Results
R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
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> library(AGSDest)
> png(filename="/home/ddbj/snapshot/RGM3/R_CC/result/AGSDest/plan.GST.Rd_%03d_medium.png", width=480, height=480)
> ### Name: plan.GST
> ### Title: Plans a group sequential trial (GST)
> ### Aliases: plan.GST
> ### Keywords: methods
>
> ### ** Examples
>
> ##The following plans an O'Brien and Flaming group sequential design (GSD)
> ##with 4 stages and equally spaced looks.
> pT <- plan.GST(K=4, SF=1, phi=0, alpha=0.025, delta=6, pow=0.8, compute.alab=TRUE, compute.als=TRUE)
>
>
>
>
>
> dev.off()
null device
1
>