Function to extract transition probabilities and (co)variance
The trprob method is used to extract transition probabilities,
while trcov is used to obtain the (co)variance.
## S3 method for class 'etm' trprob(x, tr.choice, timepoints, ...) ## S3 method for class 'etm' trcov(x, tr.choice, timepoints, ...)
x |
An object of class |
tr.choice |
A character vector of the form "from to" describing
for which transition one wishes to obtain the transition probabilities
or covariance estimates. For |
timepoints |
Time points at which one want the estimates. When missing, estimates are obtained for all event times. |
... |
Further arguments. |
A vector containing the transition probabilities or covariance
estimates either at the time specified in timepoints or at all
transition times.
Arthur Allignol, arthur.allignol@gmail.com
data(sir.cont)
# Modification for patients entering and leaving a state
# at the same date
# Change on ventilation status is considered
# to happen before end of hospital stay
sir.cont <- sir.cont[order(sir.cont$id, sir.cont$time), ]
for (i in 2:nrow(sir.cont)) {
if (sir.cont$id[i]==sir.cont$id[i-1]) {
if (sir.cont$time[i]==sir.cont$time[i-1]) {
sir.cont$time[i-1] <- sir.cont$time[i-1] - 0.5
}
}
}
### Computation of the transition probabilities
# Possible transitions.
tra <- matrix(ncol=3,nrow=3,FALSE)
tra[1, 2:3] <- TRUE
tra[2, c(1, 3)] <- TRUE
# etm
fit.etm <- etm(sir.cont, c("0", "1", "2"), tra, "cens", 0)
## extract P_01(0, t) and variance
p01 <- trprob(fit.etm, "0 1")
var.p01 <- trcov(fit.etm, "0 1")
## covariance between P_00 and P_01
cov.00.01 <- trcov(fit.etm, c("0 0", "0 1"))
## P_01 at some time points
trprob(fit.etm, "0 1", c(0, 15, 50, 100))Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.