gsrsb (version 1.2.1)

ldSecondaryBoundary: Calculate Refined Secondary Boundary, Error Spending Approach

Description

Refined secondary boundaries are calculated by using the error spending approach.

Usage

ldSecondaryBoundary(
  alpha,
  tVec,
  cvec,
  locPeak,
  type = 2,
  initIntvl = c(0.6, 4)
)

Value

refined secondary boundaries.

Arguments

alpha

original significance level.

tVec

information vector.

cvec

primary group sequential boundary.

locPeak

location of maximum, a number between 1 and the number of interims.

type

type of the test procedure for the secondary endpoint. O'Brien- Fleming (OBF) type error spending funciton is 1, Pocock (POC) type error spending funciton is 2.

initIntvl

computing paramter, a pair of numbers containing the end-points of the interval to be searched for the root.

Author

Jiangtao Gou

Details

This function calculates the refined secondary boundaries of any Lan-DeMets error spending boundary based on the primary boundaries.

References

Lan, K. K. G., and Demets, D. L. (1983). Discrete sequential boundaries for clinical trials. Biometrika 70, 659-663.

Tamhane, A. C., Gou, J., Jennison, C., Mehta, C. R., and Curto, T. (2017+). A gatekeeping procedure to test a primary and a secondary endpoint in a group sequential design with multiple interim looks. Biometrics, 74, 40-48.

See Also

secondaryBoundary, secondaryBoundaryVecLD

Examples

if (FALSE) {
require(mvtnorm)
require(ldbounds)
K <- 6;
tVec <- c(140,328,453,578,659,1080)/1080;
alpha = 0.025;
cvec.obf <- ldbounds::ldBounds(t=tVec,iuse=c(1),alpha=c(alpha),sides = 1);
cvec <- cvec.obf$upper.bounds;
secbound <- ldSecondaryBoundary(alpha,tVec,cvec,locPeak=4,type=2,
    initIntvl=c(0.8,8))
}