Create a Survival Object

This function just calls Surv() from the survival package.

Usage

Surv(time, time2, event, type = c("right", "left", "interval", "counting",
  "interval2"), origin = 0)

Arguments

time

for right censored data, this is the follow up time. For interval data, the first argument is the starting time for the interval.

time2

ending time of the interval for interval censored or counting process data only. Intervals are assumed to be open on the left and closed on the right, (start, end]. For counting process data, event indicates whether a transtion to another state occurred at the end of the interval.

event

The status indicator, normally 0=alive, 1=dead. Other choices are TRUE/FALSE (TRUE = death), 1/2 (2=death), or a factor variable. For interval censored data, the status indicator is 0=right censored, 1=event at time, 2=left censored, 3=interval censored. For multiple endpoint data the event variable will always be a factor, whose first level must correspond to "no observed transtition for this subject at this time point". There is no constraint on the labels of the factor; "none", "censored", and "alive" are common choices for the first level. Although unusual, the event indicator can be omitted, in which case all subjects are assumed to have an event.

type

character string specifying the type of censoring. Possible values are "right", "left", "counting", "interval", "interval2". The default is multi-state if event is a factor, counting process if time2 is present, or right censored, in that order.

origin

for counting process data, the hazard function origin. This option was intended to be used in conjunction with a model containing time dependent strata in order to align the subjects properly when they cross over from one strata to another, but it has rarely proven useful and is depricated.