survfit.object           package:survival           R Documentation

_S_u_r_v_i_v_a_l _C_u_r_v_e _O_b_j_e_c_t

_D_e_s_c_r_i_p_t_i_o_n:

     This class of objects is returned by the 'survfit' class of
     functions to represent a fitted survival curve. 

     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. Class of objects that
     represent a fitted survival curve.

_A_r_g_u_m_e_n_t_s:

       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.  

 std.err: the standard error of the cumulative hazard or
          -log(survival).  

   upper: upper confidence limit for the survival curve.  

   lower: lower confidence limit for the survival curve.  

  strata: if there are multiple curves, this component gives the number
          of elements of  the 'time' etc. vectors corresponding to the
          first curve, the second curve,  and so on.  The names of the
          elements are labels for the curves.  

start.time: the value specified for the 'start.time' argument, if it
          was used in the call.   

   n.all: for counting process data, and any time that the 
          'start.time' argument was used, this contains the total
          number of observations that were available. Not all may have
          been used in creating the curve, in which case this value
          will be larger than 'n' above. of observations that were
          available 

conf.type: the approximation used to compute the confidence limits.  

conf.int: the level of the confidence limits, e.g. 90 or 95%.  

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.  

_S_t_r_u_c_t_u_r_e:

     The following components must be included in a legitimate 
     'survfit'  object.

_S_u_b_s_c_r_i_p_t_s:

     Survfit objects that contain multiple survival curves can be
     subscripted.  This is most often used to plot a subset of the
     curves.  Usually a single subscript will be used.  In one
     particular case - survival curves for multiple covariate values,
     from a Cox model that includes  a 'strata' statement - there is a
     matrix of  curves and 2 subscripts may be used.  (In this case
     'summary.survfit' will  also print the data as a matrix).

_S_e_e _A_l_s_o:

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