Package 'tauProcess'

Title: Tau Measure with Right-Censored Data
Description: A clinically meaningful measures of treatment effects for right-censored data are provided, based on the concept of Kendall's tau, along with the corresponding inference procedures. Two plots of tau processes, with the option to account for the cure fraction or not, are available. The plots of tau processes serve as useful graphical tools for monitoring the relative performances over time.
Authors: Yi-Cheng Tai [aut, cre, cph] , Weijing Wang [aut] , Martin T. Wells [aut]
Maintainer: Yi-Cheng Tai <[email protected]>
License: MIT + file LICENSE
Version: 2.1.3
Built: 2025-01-30 04:39:25 UTC
Source: https://github.com/s07308/tauprocess

Help Index


Mayo Clinic Primary Biliary Cholangitis Data

Description

This dataset is obtained from 'pbc' in package 'survival' by excluding the non-randomized individuals. For background and details of the original dataset, please refer to the document page of 'survival'.

Usage

pbc

Format

pbc

A data frame with 258 rows and 3 columns:

surv.time

the survival of each subject in the trial (days)

event

censoring indicator (1: dead; 0: censored)

arm

treatment arm (1: D-penicillamine; 0: placebo)

Source

https://cran.r-project.org/package=survival


Plot the Tau Process with/without cure fraction

Description

This function plot the estimated tau process with/withour cure fraction obtained from tau_proc. It can be used to monitor the progression of treatment effect (for susceptible subgroups).

Usage

## S3 method for class 'tau_process'
plot(x, ...)

Arguments

x

an object of class "tau_process", returned by tau_proc function

...

additional arguments passed to underlying plot method

Value

a list with components x and y.

Examples

fit <- tau_proc(pbc$surv.time, pbc$event, pbc$arm)
plot(fit)

Plot the Tau Process

Description

This function plot the estimated tau process obtained from tau.fit. It can be used to monitor the progression of treatment effect.

Usage

## S3 method for class 'tauFit'
plot(x, ...)

Arguments

x

an object of class "tauFit", returned by tau.fit function

...

additional arguments passed to underlying plot method

Value

a list with components x and y.

Examples

fit <- tau.fit(pbc$surv.time, pbc$event, pbc$arm)
plot(fit, type = "b")

Print Method for "summaryTauFit" Objects

Description

user-friendly format to present the inference results obtained from summary.tauFit.

Usage

## S3 method for class 'summaryTauFit'
print(x, ...)

Arguments

x

an object of class "summaryTauFit"

...

additional arguments passed to underlying printCoefmat method.

Value

None

Examples

fit <- tau.fit(pbc$surv.time, pbc$event, pbc$arm)
summary(fit)

Summarize the Inference Result of Tau Process at Last Specified Time

Description

This function summarizes the inference results obtained from tau.fit. The results under random grouping design (complete randomization design) and fixed grouping design (random allocation rule / urn model) would be almost the same with large sample size.

Usage

## S3 method for class 'tauFit'
summary(object, conf.int = 0.95, ...)

Arguments

object

an object of class "tauFit"

conf.int

the significance level of the confidence interval

...

additional arguments passed to underlying summary method

Value

an object of class "summaryTauFit"

Examples

fit <- tau.fit(pbc$surv.time, pbc$event, pbc$arm)
summary(fit)

Estimate the Tau Process with/without cure fraction

Description

Estimate the Tau Process with/without cure fraction

Usage

tau_proc(time, status, arm, t = NULL, cure = FALSE)

Arguments

time

a numerical vector of survival times.

status

endpoint status (0 for censored, 1 for deceased).

arm

treatment group indicator (1 for treated, 0 for control).

t

a sequence of specified times. If the user do not specify the sequence, the default is an equally-spaced sequence from 0 to the last identified time.

cure

a boolean variable indicating whether to consider the cure fractions.

Details

The estimation method proposed by Yi-Cheng Tai, Weijing Wang and Martin T. Wells to estimate tau process with or without cure fraction.

Value

an object of class "tau_process" with components

t the specified sequence of time points
vals_tau_proc the estimated value of tau measure at given time
cure a boolean variable indicating whether to consider the cure fraction
cure_rates the estimated cure rates for Group 0 and Group 1, respectively

Examples

tau_proc(pbc$surv.time, pbc$event, pbc$arm, cure = TRUE)

Estimate the Tau Process

Description

Estimate the tau process at specified time points. The estimated variances at the last time point under complete randomization design and random allocation rule (urn model) are provided.

Usage

tau.fit(time, status, arm, t = numeric())

Arguments

time

a numerical vector of survival times.

status

endpoint status (0 for censored, 1 for deceased).

arm

treatment group indicator (1 for treated, 0 for control).

t

a sequence of specified times. If the user do not specify the sequence, the default is an equally-spaced sequence from 0 to the last identified time.

Details

The estimation and inference procedure are proposed by Yi-Cheng Tai, Weijing Wang and Martin T. Wells. The value of tau measure serves as a clinically meaningful measure of treatment effect. It supplements the traditional hazard ratio (HR) under nonproportional hazard scenario.

Value

an object of class "tauFit" with components

N0 number of individuals with arm=0
N1 number of individuals with arm=1
t the specified truncation time
tau the estimated value of tau measure
var.r the estimated variance under random grouping design (complete randomization design)
var.f the estimated variance under fixed grouping design (random allocation rule / urn model)

Examples

tau.fit(pbc$surv.time, pbc$event, pbc$arm)