dindex.comp.meta {survcomp} | R Documentation

## Function to compare two D indices

### Description

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

### Usage

    dindex.comp.meta(list.dindex1, list.dindex2, hetero = FALSE)

### Arguments

`list.dindex1` | first list of D indices as returned by the `D.index` function.
`list.dindex2` | second list of D indices as returned by the `D.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 D indices. The two lists of D 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 dindex1 > dindex2.
`dindex1` | meta-estimator of the first D index.
`dindex2` | meta-estimator of the second D 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)
    d1.1 <- D.index(x=age, surv.time=stime, surv.event=sevent)
    d2.1 <- D.index(x=size, surv.time=stime, surv.event=sevent)
    #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)
    d1.2 <- D.index(x=age, surv.time=stime, surv.event=sevent)
    d2.2 <- D.index(x=size, surv.time=stime, surv.event=sevent)
    dindex.comp.meta(list.dindex1=list("dindex.age1"=d1.1, "dindex.age2"=d1.2),
      list.dindex2=list("dindex.size1"=d2.1, "dindex.size2"=d2.2))

[Package survcomp version 1.44.1 Index]