cindex.comp.meta {survcomp} | R Documentation

## Function to compare two concordance indices

### Description

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

### Usage

    cindex.comp.meta(list.cindex1, list.cindex2, hetero = FALSE)

### Arguments

`list.cindex1` | first list of concordance indices as returned by the `concordance.index` function.
`list.cindex2` | second list of concordance indices as returned by the `concordance.index` function.
`hetero` | if TRUE, a random effect model is use to compute the meta-estimators. Otherwise a fixed effect model is used.

### Details

In meta-analysis, we estimate the statistic of interest in several independent datasets. It results a list of estimates such as list of concordance indices. The two lists of concordance indices must be computed from the same samples (and corresponding survival data). The function computes a meta-estimator for the correlations between the two scores and uses a Student t test for dependent samples.

### Value

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

### Author(s)

Benjamin Haibe-Kains

### References

Cochrane, W. G. (1954) "The combination of estimates from different experiments", Biometrics, 10, pages 101–129.

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

    #first dataset
    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)
    c1.1 <- concordance.index(x=age, surv.time=stime, surv.event=sevent,
      method="noether")
    c2.1 <- concordance.index(x=size, surv.time=stime, surv.event=sevent,
      method="noether")
    #second dataset
    set.seed(54321)
    age <- rnorm(110, 53, 10)
    size <- rexp(110,1.1)
    stime <- rexp(110)
    cens <- runif(110,.55,2)
    sevent <- as.numeric(stime <= cens)
    stime <- pmin(stime, cens)
    c1.2 <- concordance.index(x=age, surv.time=stime, surv.event=sevent,
      method="noether")
    c2.2 <- concordance.index(x=size, surv.time=stime, surv.event=sevent,
      method="noether")
    cindex.comp.meta(list.cindex1=list("cindex.age1"=c1.1, "cindex.age2"=c1.2),
      list.cindex2=list("cindex.size1"=c2.1, "cindex.size2"=c2.2))

[Package survcomp version 1.44.1 Index]