cindex.comp {survcomp} | R Documentation

## 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.

### 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)

[Package survcomp version 1.40.0 Index]