cindex.comp: Function to compare two concordance indices

In survcomp: Performance Assessment and Comparison for Survival Analysis

Description

This function compares two concordance indices computed from the same data by using the function concordance.index. The statistical test is a Student t test for dependent samples.

Usage

cindex.comp(cindex1, cindex2)

Arguments

cindex1	first concordance index as returned by the concordance.index function.
cindex2	second concordance index as returned by the concordance.index function.

Details

The two concordance indices must be computed from the same samples (and corresponding survival data). The function uses a Student t test for dependent samples.

Value

p.value	p-value from the Student t test for the comparison cindex1 > cindex2.
cindex1	value of the first concordance index.
cindex2	value of the second concordance index.

Author(s)

Benjamin Haibe-Kains

References

Haibe-Kains, B. and Desmedt, C. and Sotiriou, C. and Bontempi, G. (2008) "A comparative study of survival models for breast cancer prognostication based on microarray data: does a single gene beat them all?", Bioinformatics, 24(19), pages 2200–2208.

See Also

concordance.index.

Examples

set.seed(12345)
age <- rnorm(100, 50, 10)
size <- rexp(100,1)
stime <- rexp(100)
cens <- runif(100,.5,2)
sevent <- as.numeric(stime <= cens)
stime <- pmin(stime, cens)
c1 <- concordance.index(x=age, surv.time=stime, surv.event=sevent,
  method="noether")
c2 <- concordance.index(x=size, surv.time=stime, surv.event=sevent,
  method="noether")
cindex.comp(c1, c2)

Example output

Loading required package: survival
Loading required package: prodlim
$p.value
[1] 0.005242669

$cindex1
[1] 0.5774342

$cindex2
[1] 0.4358541

survcomp documentation built on Nov. 8, 2020, 4:54 p.m.