print.survfit            package:survival            R Documentation

_P_r_i_n_t _a _S_h_o_r_t _S_u_m_m_a_r_y _o_f _a _S_u_r_v_i_v_a_l _C_u_r_v_e

_D_e_s_c_r_i_p_t_i_o_n:

     Print number of observations, number of events, the restricted
     mean survival and its   standard error, and the median survival
     with confidence limits for the   median.

_U_s_a_g_e:

     ## S3 method for class 'survfit':
     print(x, scale=1, digits = max(options()$digits - 4,3),
         print.rmean=getOption("survfit.print.rmean"),
         rmean = getOption('survfit.rmean'),...)

_A_r_g_u_m_e_n_t_s:

       x: the result of a call to the 'survfit' function.  

   scale: a numeric value to rescale the survival time, e.g.,  if the
          input data to survfit were in days,  'scale=365' would scale
          the printout to years.  

  digits: Number of digits to print

print.rmean,rmean: Options for computation and display of the
          restricted mean.

     ...: for future results

_D_e_t_a_i_l_s:

     The mean and its variance are based on a truncated estimator. 
     That is, if the  last observation(s) is not a death, then the
     survival curve estimate does not  go to zero and the mean is
     undefined. There are four possible approaches, which are selected
     by the 'rmean' option. The first is to set the upper limit to a
     constant, e.g.,'rmean=365'. In this case the reported mean would
     be the expected number of days, out of the first 365, that would
     be experienced by each group.  This is useful if interest focuses
     on a fixed period. Other options are '"none"' (no estimate),
     '"common"' and '"individual"'. For the last of these, the mean is
     computed as the area under the curve, over the range from 0 to the
     maximum observed time for that curve. Since the end point is
     random, values for different curves are not comparable and the
     printed standard errors are an underestimate as they do not take
     into account this random variation.  This option is provided
     mainly for backwards compatability, as this estimate was the
     default (only) one in earlier releases of the code. The '"common"'
     option uses the maximum time for all curves in the object as a
     common upper limit for the auc calculation.

     The median and its confidence interval are defined by drawing a
     horizontal  line at 0.5 on the plot of the survival curve and its
     confidence bands.  The intersection of the line with the lower CI
     band defines the lower limit  for the median's interval, and
     similarly for the upper band.  If any of the  intersections is not
     a point, then we use the smallest point of intersection,  e.g., if
     the survival curve were exactly equal to 0.5 over an interval.

_V_a_l_u_e:

     x, with the invisible flag set to prevent printing.

_S_i_d_e _E_f_f_e_c_t_s:

     he number of observations, the number of events,  the median
     survival with its confidence interval, and optionally the
     restricted mean survival ('rmean') and its standard error, are
     printed. If there are multiple curves, there is one line of output
     for each.

_R_e_f_e_r_e_n_c_e_s:

     Miller, Rupert G., Jr. (1981).   _Survival Analysis._ New
     York:Wiley, p 71.

_S_e_e _A_l_s_o:

     'summary.survfit'.