R: Bootstrap function in multi-state models

msboot {mstate} | R Documentation

## Bootstrap function in multi-state models

### Description

A generic nonparametric bootstrapping function for multi-state models.

### Usage

    msboot(theta, data, B = 5, id = "id", verbose = 0, ...)

### Arguments

`theta` | A function of `data` and perhaps other arguments, returning the value of the statistic to be bootstrapped; the output of theta should be a scalar or numeric vector
`data` | An object of class 'msdata', such as output from `msprep`
`B` | The number of bootstrap replications; the default is taken to be quite small (5) since bootstrapping can be time-consuming
`id` | Character string indicating which column identifies the subjects to be resampled
`verbose` | The level of output; default 0 = no output, 1 = print the replication
`...` | Any further arguments to the function `theta`

### Details

The function `msboot` samples randomly with replacement subjects from the original dataset `data`. The individuals are identified with `id`, and bootstrap datasets are produced by concatenating all selected rows.

### Value

Matrix of dimension (length of output of theta) x B, with b'th column being the value of theta for the b'th bootstrap dataset

### Author(s)

Marta Fiocco, Hein Putter <H.Putter@lumc.nl>

### References

Fiocco M, Putter H, van Houwelingen HC (2008). Reduced-rank proportional hazards regression and simulation-based prediction for multi-state models. Statistics in Medicine 27, 4340–4358.

### Examples

    tmat <- trans.illdeath()
    data(ebmt1)
    covs <- c("score","yrel")
    msebmt <- msprep(time=c(NA,"rel","srv"),status=c(NA,"relstat","srvstat"),
    		data=ebmt1,id="patid",keep=covs,trans=tmat)
    # define a function (this one returns vector of regression coef's)
    regcoefvec <- function(data) {
      cx <- coxph(Surv(Tstart,Tstop,status)~score+strata(trans),
              data=data,method="breslow")
      return(coef(cx))
    }
    regcoefvec(msebmt)
    set.seed(1234)
    msboot(theta=regcoefvec,data=msebmt,id="patid")

[Package mstate version 0.3.1 Index]