getBound: Efficacy Boundaries for Group Sequential Design

In lrstat: Power and Sample Size Calculation for Non-Proportional Hazards and Beyond

Efficacy Boundaries for Group Sequential Design

Description

Obtains the efficacy stopping boundaries for a group sequential design.

Usage

getBound(
  k = NA_integer_,
  informationRates = NA_real_,
  alpha = 0.025,
  typeAlphaSpending = "sfOF",
  parameterAlphaSpending = NA_real_,
  userAlphaSpending = NA_real_,
  spendingTime = NA_real_,
  efficacyStopping = NA_integer_
)

Arguments

k	Look number for the current analysis.
informationRates	Information rates up to the current look. Must be increasing and less than or equal to 1.
alpha	The significance level. Defaults to 0.025.
typeAlphaSpending	The type of alpha spending. One of the following: "OF" for O'Brien-Fleming boundaries, "P" for Pocock boundaries, "WT" for Wang & Tsiatis boundaries, "sfOF" for O'Brien-Fleming type spending function, "sfP" for Pocock type spending function, "sfKD" for Kim & DeMets spending function, "sfHSD" for Hwang, Shi & DeCani spending function, "user" for user defined spending, and "none" for no early efficacy stopping. Defaults to "sfOF".
parameterAlphaSpending	The parameter value for the alpha spending. Corresponds to \Delta for "WT", \rho for "sfKD", and \gamma for "sfHSD".
userAlphaSpending	The user defined alpha spending. Cumulative alpha spent up to each stage.
spendingTime	A vector of length k for the error spending time at each analysis. Must be increasing and less than or equal to 1. Defaults to missing, in which case, it is the same as informationRates.
efficacyStopping	Indicators of whether efficacy stopping is allowed at each stage. Defaults to TRUE if left unspecified.

Details

If typeAlphaSpending is "OF", "P", "WT", or "none", then informationRates, efficacyStopping, and spendingTime must be of full length kMax, and informationRates and spendingTime must end with 1.

Value

A numeric vector of critical values up to the current look.

Author(s)

Kaifeng Lu, [e-mail]

Examples

getBound(k = 2, informationRates = c(0.5,1),
         alpha = 0.025, typeAlphaSpending = "sfOF")

lrstat documentation built on May 13, 2026, 9:06 a.m.