mdir.logrank: Two-sample multiple-direction log rank test

In mdir.logrank: Multiple-Direction Logrank Test

Description

The mdir.logrank function calculates the multiple-direction logrank statistic and its corresponding p-values based on a χ^2-approximation and a permutation approach

Usage

mdir.logrank(data, cross = TRUE, rg = list(c(0, 0)), nperm = 10000,
  dig_p = 3, dig_stat = 3)

Arguments

data	A data.frame, list or environment containing the variables time, event (with values 0 for censored and 1 for uncensored) and group.
cross	logical. Should the weight corresponding to crossing hazards be included? The default is TRUE.
rg	A list (or NULL) containing the exponents c(r, g) of the directions w(x) = x^r (1-x)^g. Both exponents r,g need to be natural numbers including 0. Default is list(c(0, 0)) corresponding to proportional hazards.
nperm	The number of permutations used for calculating the permuted p-value. The default option is 10000.
dig_p	The p-values are rounded to dig_p digits, the default is 3.
dig_stat	The test statistic is rounded to dig_stat digits, the default is 3.

Details

The package provides the multiple-direction logrank statistic for the two sample testing problem within right-censored survival data. Directions of the form w(x) = 1 - 2x (cross = TRUE) and w(x) = x^r * (1-x)^g for natural numbers r,g (including 0) can be specified. The multiple-direction logrank test needs linearly independent directions. A check for this is implemented. If the directions chosen by the user are linearly dependent then a subset consisting of linearly independent directions is selected automatically.

The mdir.logrank function returns the test statistic as well as two corresponding p-values: the first is based on a chi^2 approximation and the second one is based on a permutation procedure.

Value

An mdirLR object containing the following components:

Descriptive	The directions used and whether the directions specified by the user were linearly independent.
p.values	The p-values of the multiple-direction logrank test using the χ^2-approximation (Approx.) as well as the one using the permutation approach (Perm.).
stat	Value of the multiple-direction logrank statistic.
rg	A list containing the exponents of the direction considered in the statistical analysis.
cross	logical. Was the crossing direction considered in the statistical analysis?
indep	logical. Were the directions specified by the user linearly independent?
nperm	The number of permutations used for calculating the permuted p-value.

References

Ditzhaus, M., Friedrich, S. (2018). More powerful logrank permutation tests for two-sample survival data. arXiv preprint arXiv:1807.05504.

See Also

mdir.onesided (one-sided test)

Examples

library(coin)
data(GTSG)
out <- mdir.logrank(data = GTSG, nperm = 1000)

## Detailed information:
summary(out)

mdir.logrank documentation built on May 2, 2019, 4:21 a.m.