Generates synthetic event indicator and time to event data using classification and regression trees (without or with bootstrap).
syn.survctree(y, yevent, x, xp, proper = FALSE, minbucket = 5, ...)a vector of length n with original time data.
a vector of length n with original event indicator data.
a matrix (n x p) of original covariates.
a matrix (k x p) of synthesised covariates.
for proper synthesis (proper = TRUE) a CART
model is fitted to a bootstrapped sample of the original data.
the minimum number of observations in
any terminal node. See ctree_control
for details.
additional parameters passed to ctree.
A list with the following components:
a vector of length k with synthetic time values.
a vector of length k with synthetic event indicator values.
The procedure for synthesis by a CART model is as follows:
For each xp find the terminal node.
Randomly
draw a donor from the members of the node and take the observed
value of yevent and y from that draw as the
synthetic values.
NOTE that when the function is called by setting elements of method in
syn() to "survctree", the parameter minbucket
can be supplied to syn() as e.g. survctree.minbucket.