Sample from an mjoint object — sampleData • joineRML

Generic function used to sample a subset of data from an object of class mjoint with a specific number of subjects.

Usage

sampleData(object, size = NULL, replace = TRUE)

Arguments

object: an object inheriting from class mjoint for a joint model of time-to-event and multivariate longitudinal data.
size: number of subjects to include in the sampled subset. If size=NULL (default), then size is set equal to the number of subjects used to fit the mjoint model.
replace: use replacement when sampling subjects? Default is TRUE. If replacement is used, then the subjects are re-labelled from 1 to size.

Value

A list of 2 data.frames: one recording the requisite longitudinal outcomes data, and the other recording the time-to-event data.

Details

This function is primarily intended for internal use in the bootSE function in order to permit bootstrapping. However, it can be used for other purposes given a fitted mjoint object.

Author

Graeme L. Hickey (graemeleehickey@gmail.com)

Examples

if (FALSE) { # \dontrun{
# Fit a joint model with bivariate longitudinal outcomes

data(heart.valve)
hvd <- heart.valve[!is.na(heart.valve$log.grad) & !is.na(heart.valve$log.lvmi), ]

fit2 <- mjoint(
    formLongFixed = list("grad" = log.grad ~ time + sex + hs,
                         "lvmi" = log.lvmi ~ time + sex),
    formLongRandom = list("grad" = ~ 1 | num,
                          "lvmi" = ~ time | num),
    formSurv = Surv(fuyrs, status) ~ age,
    data = list(hvd, hvd),
    inits = list("gamma" = c(0.11, 1.51, 0.80)),
    timeVar = "time",
    verbose = TRUE)
sampleData(fit2, size = 10)
} # }

Sample from an `mjoint` object