getCI_mams: Confidence Interval After Trial Termination for Multi-Arm...

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

Confidence Interval After Trial Termination for Multi-Arm Multi-Stage Design

Description

Obtains the p-value, conservative point estimate, and confidence interval after the end of a multi-arm multi-stage trial.

Usage

getCI_mams(
  M = NA_integer_,
  r = 1,
  corr_known = TRUE,
  L = NA_integer_,
  zL = NA_real_,
  IMax = NA_real_,
  informationRates = NA_real_,
  efficacyStopping = NA_integer_,
  criticalValues = NULL,
  alpha = 0.025,
  typeAlphaSpending = "sfOF",
  parameterAlphaSpending = NA_real_,
  spendingTime = NA_real_
)

Arguments

M	Number of active treatment arms.
r	Randomization ratio of each active arm to the common control.
corr_known	Logical. If TRUE, the correlation between Wald statistics is derived from the randomization ratio r as r / (r + 1). If FALSE, a conservative correlation of 0 is used.
L	The termination look.
zL	The vector of z-test statistics at the termination look.
IMax	Maximum information for any active arm versus the common control.
informationRates	The information rates up to look L.
efficacyStopping	Indicators of whether efficacy stopping is allowed at each stage up to look L. Defaults to TRUE if left unspecified.
criticalValues	The matrix of by-level upper boundaries on the max z-test statistic scale for efficacy stopping up to look L. The first column is for level M, the second column is for level M - 1, and so on, with the last column for level 1. If left unspecified, the critical values will be computed based on the specified alpha spending function.
alpha	The significance level. Defaults to 0.025.
typeAlphaSpending	The type of alpha spending for the trial. 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, 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".
spendingTime	The error spending time up to look L. Defaults to missing, in which case, it is the same as informationRates.

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 data frame with the following components:

• level: Number of individual hypotheses considered for multiplicity.

• index: The treatment arm with max Z among the active arms.

• pvalue: p-value for rejecting the null hypothesis.

• thetahat: Point estimate of the parameter.

• cilevel: Confidence interval level.

• lower: Lower bound of confidence interval.

• upper: Upper bound of confidence interval.

Author(s)

Kaifeng Lu, [e-mail]

References

Ping Gao, Yingqiu Li. Adaptive multiple comparison sequential design (AMCSD) for clinical trials. Journal of Biopharmaceutical Statistics, 2024, 34(3), 424-440.

Examples

getCI_mams(
  L = 2, zL = c(2.075, 2.264),
  M = 2, r = 1, corr_known = FALSE,
  IMax = 300 / 4, informationRates = c(1/2, 1),
  alpha = 0.025, typeAlphaSpending = "sfOF")

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