survcomp (version 1.22.0)

cindex.comp: Function to compare two concordance indices

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.

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.

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.

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)