survfit.object {survival}  R Documentation 
This class of objects is returned by the survfit
class of functions
to represent a fitted survival curve.
For a multistate model the object has class c('survfitms', 'survfit')
.
Objects of this class have methods for the functions print
,
summary
, plot
, points
and lines
. The
print.survfit
method does more computation than is typical
for a print method and is documented on a separate page.
n 
total number of subjects in each curve. 
time 
the time points at which the curve has a step. 
n.risk 
the number of subjects at risk at t. 
n.event 
the number of events that occur at time t. 
n.enter 
for counting process data only, the number of subjects that enter at time t. 
n.censor 
for counting process data only, the number of subjects who exit the risk set, without an event, at time t. (For right censored data, this number can be computed from the successive values of the number at risk). 
surv 
the estimate of survival at time t+0. This may be a vector or a matrix. The latter occurs when a set of survival curves is created from a single Cox model, in which case there is one column for each covariate set. 
prev, p0 
a multistate survival will have the 
std.err 
for a survival curve this contains standard error of the cumulative hazard or log(survival), for a multistate curve it contains the standard error of prev. This difference is a reflection of the fact that each is the natural calculation for that case. 
cumhaz hazard 
optional. For a multistate curve this is an k by k array for each time point, where k is the number of states. 
upper 
upper confidence limit for the survival curve or probability 
lower 
lower confidence limit for the survival curve or probability 
strata 
if there are multiple curves, this component gives the number of elements of
the 
start.time 
the value specified for the 
n.all 
for counting process data, and any time that the

conf.type 
the approximation used to compute the confidence limits. 
conf.int 
the level of the confidence limits, e.g. 90 or 95%. 
transitions 
for multistate data, the total number of transitions of each type. 
na.action 
the returned value from the na.action function, if any. It will be used in the printout of the curve, e.g., the number of observations deleted due to missing values. 
call 
an image of the call that produced the object. 
type 
type of survival censoring. 
influence 
optional, for survfitms objects only.
A list with one element per stratum, each
element of the list is an array indexed by subject, time, state.
The time dimension will have one more element than the 
The following components must be included in a legitimate
survfit
or survfitms
object.
Survfit objects that contain multiple survival curves can be subscripted.
This is often used to plot a subset of the curves.
If the surv
or prev
component is a matrix then the
survfit
object will be treated as a matrix, otherwise only a
single subscript is used.
plot.survfit
,
summary.survfit
,
print.survfit
,
survfit
.