The frailty function for adding a simple random effects term to the linear predictor of a given survival regression model.
Usage
rfrailty(
cluster,
frailty = c("gamma", "gaussian", "ps"),
sigma = 1,
alpha = NULL,
...
)Arguments
- cluster
a vector determining the grouping of subjects (always converted to a factor object internally.
- frailty
the frailty distribution; current implementation includes the gamma (default), lognormal and positive stable (ps) distributions.
- sigma
standard deviation assumed for the frailty distribution; sigma = 1 by default; this value is ignored for positive stable (ps) distribution.
- alpha
stability parameter of the positive stable distribution; alpha must lie in (0,1) interval and an NA is return otherwise.
- ...
further arguments passed to other methods.