ibsc.comp {survcomp} | R Documentation

## Function to compare two IBSCs

### Description

This function compares two integrated Briers scores (IBSC) through the estimation of the Brier scores (BSC) at some points in time. The statistical test is a Wilcoxon rank sum test for dependent samples.

### Usage

    ibsc.comp(bsc1, bsc2, time)

### Arguments

`bsc1` | vector of BSCs computed from the first predicted probabilities for some points in time
`bsc2` | vector of BSCs computed from the second predicted probabilities for some points in time
`time` | vector of points in time for which the BSCs are computed

### Details

The two vectors of BSCs must be computed from the same samples (and corresponding survival data) and for the same points in time. The function uses a Wilcoxon rank sum test for dependent samples.

### Value

`p.value` | p-value from the Wilcoxon rank sum test for the comparison ibsc1 < ibsc2
`ibsc1` | value of the IBSC for the first set of BSCs
`ibsc2` | value of the IBSC for the second set of BSCs

### Author(s)

Benjamin Haibe-Kains

### References

Wilcoxon, F. (1945) "Individual comparisons by ranking methods", Biometrics Bulletin, 1, pages 80–83.

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

`sbrier.score2proba`, `sbrier`

### Examples

    set.seed(12345)
    age <- rnorm(30, 50, 10)
    size <- rexp(30,1)
    stime <- rexp(30)
    cens <- runif(30,.5,2)
    sevent <- as.numeric(stime <= cens)
    stime <- pmin(stime, cens)
    ##Brier scores
    ##size
    dd <- data.frame("time"=stime, "event"=sevent, "score"=size)
    bsc1 <- sbrier.score2proba(data.tr=dd, data.ts=dd, method="cox")
    ##size
    dd <- data.frame("time"=stime, "event"=sevent, "score"=age)
    bsc2 <- sbrier.score2proba(data.tr=dd, data.ts=dd, method="cox")
    if(!all(bsc1$time == bsc2$time)) {
      stop("the two vector of BSCs must be computed for the same points in time!") }
    ibsc.comp(bsc1=bsc1$bsc, bsc2=bsc2$bsc, time=bsc1$time)

[Package survcomp version 1.40.0 Index]