strata

0th

Percentile

Identify Strata Variables

This is a special function used in the context of the Cox survival model. It identifies stratification variables when they appear on the right hand side of a formula.

Keywords
survival
Usage
strata(..., na.group=F, shortlabel=F)
Arguments
...
any number of variables. All must be the same length.
na.group
a logical variable, if TRUE, then missing values are treated as a distinct level of each variable.
shortlabel
if TRUE omit variable names from resulting factor labels
Details

The result is identical to the interaction function, but for the labeling of the factors (strata is more verbose).

Value

  • a new factor, whose levels are all possible combinations of the factors supplied as arguments.

See Also

coxph,interaction

Aliases
  • strata
Examples
a<-factor(rep(1:3,4))
b<-factor(rep(1:4,3))
levels(strata(a))
levels(strata(a,b,shortlabel=TRUE))
data(ovarian)
coxph(Surv(futime, fustat) ~ age + strata(rx), data=ovarian)
Documentation reproduced from package survival, version 2.9-6, License: GPL2

Community examples

Looks like there are no examples yet.