TwoSample.Z.Var.Estimator.Sequential.TTFE: Function to calculate the two-sample time-to-first-event...

In gsMeanFreq: Group Sequential Clinical Trial Designs for Composite Endpoints

Function to calculate the two-sample time-to-first-event (TTFE) statistics and variances across multiple calendar times.

Description

Computes sequential Z-statistics and their corresponding variance estimates for a two-sample time-to-first-event (TTFE) analysis at a set of prespecified calendar analysis times. At each calendar time, administrative censoring is applied, event times are converted from the calendar scale to the event-time scale, and a standard log-rank test is performed using only the first observed event per subject.

Usage

TwoSample.Z.Var.Estimator.Sequential.TTFE(data, tau = NULL, calendars)

Arguments

data	A data frame containing two-sample composite endpoint data, typically generated by TwoSample.generate.sequential().
tau	Optional upper bound for the event-time horizon. This argument is currently not used and is included for interface consistency with other sequential estimators in the package.
calendars	A numeric vector of calendar times at which interim analyses are conducted. Each value is treated as an administrative censoring time.

Value

A list with components:

• Z.stats: A numeric vector of log-rank Z-statistics evaluated at each calendar analysis time.

• vars: A numeric vector of estimated variances of the Z-statistics at each analysis time.

• total.ns: A numeric vector giving the total number of subjects contributing data at each calendar analysis time.

gsMeanFreq documentation built on Feb. 17, 2026, 1:07 a.m.