seqBound {sasLM}

Sequential bounds for cumulative Z-test in Group Sequential Design

Description

Sequential upper bounds for cumulative Z-test on accumaltive data. Z values are correlated. This is usually used for group sequential design.

Usage

  seqBound(ti, alpha = 0.05, side = 2, t2 = NULL, asf = 1)

Arguments

ti

times for test. These should be [0, 1].

alpha

goal alpha value for the last test at time 0.

side

1=one-side test, 2=two-side test

t2

fractions of information amount. These should be [0, 1]. If not available, ti will be used instead.

asf

alpha spending function. 1=O'Brien-Flemming, 2=Pocock, 3=alpha*ti, 4=alpha*ti^1.5, 5=alpha*ti^2

Details

It calculates upper z-bounds and cumulative alpha-values for the repeated test in group sequential design. The correlation is assumed to be sqrt(t_i/t_j).

Value

The result is a matrix.

ti

time of test

bi

upper z-bound

cum.alpha

cumulative alpha-value

Author(s)

Kyun-Seop Bae [e-mail]

References

Reboussin DM, DeMets DL, Kim K, Lan KKG. Computations for group sequential boundaries using the Lan-DeMets function method. Controlled Clinical Trials. 2000;21:190-207.

Examples

  seqBound(ti=(1:5)/5)
  seqBound(ti=(1:5)/5, asf=2)