summary.survfit           package:survival           R Documentation

Summary of a Survival Curve

Description:

     Returns a list containing the survival curve, confidence limits
     for the curve, and other information.

Usage:

     ## S3 method for class 'survfit':
     summary(object, times, censored=FALSE, scale=1, ...)

Arguments:

  object: output from a call to 'survfit'. 

   times: vector of times; the returned matrix will contain 1 row for
          each time. This must be in increasing order and missing
          values are not allowed. If 'censored=T', the default 'times'
          vector contains all the unique times in 'fit', otherwise the
          default 'times' vector uses only the event (death) times. 

censored: logical flag: should the censoring times be included in the
          output? This is ignored if the 'times' argument is present. 

   scale: rescale the survival time, e.g., if the input data to
          'survfit' were in days, 'scale=365.25' would scale the output
          to years. 

     ...: other unused arguments

Value:

     a list with the following components 

    time: the timepoint on the curve. 

    surv: the value of the survival curve at time t+0. 

  n.risk: the number of subjects at risk at time t-0 (but see the
          comments on weights in the 'survfit' help file). 

 n.event: if the 'times' argument is missing, then this column is the
          number of events that occurred at time t. Otherwise, it is
          the cumulative number of events that have occurred since the
          last time listed until time t+0. 

 std.err: the standard error of the survival value. 

conf.int: level of confidence for the confidence intervals of survival. 

   lower: lower confidence limits for the curve. 

   upper: upper confidence limits for the curve. 

  strata: indicates stratification of curve estimation.  If 'strata' is
          not 'NULL', there are multiple curves in the result and the
          'surv', 'time', 'n.risk', etc.  vectors will contain multiple
          curves, pasted end to end.  The levels of 'strata' (a factor)
          are the labels for the curves. 

    call: the statement used to create the 'fit' object. 

na.action: passed through from 'fit', if present. 

See Also:

     'survfit', 'print.summary.survfit'.

Examples:

     summary( survfit( Surv(futime, fustat),data=ovarian))
     summary( survfit( Surv(futime, fustat)~rx,data=ovarian))

