RLIFETABLE procedure

Calculates the life-table estimate of the survivor function (D.A.Murray).


Options

PRINT = strings
Controls printed output (lifetable); default life

PLOT = strings
Type of graph to be plotted (survivor, hazard, pdf); default surv, haza, pdf

INTERVAL = scalar or variate
A scalar defining the width of the intervals or a variate containing the boundaries of the intervals


Parameters

TIMES = variates
Observed timepoints

CENSORED = variates
Variate specifying whether the corresponding element of each TIMES variate is censored (1) or represents failures (0)

FREQUENCY = variates
Variate containing frequencies for the elements of TIMES; by default these are all assumed to be 1

GROUPS = factors
Factor specifying the different groups for which to estimate life tables

LIFETABLE = pointers
Pointer to variates to save the information from each life table


Description

RLIFETABLE calculates the life-table estimate, or actuarial estimate, of the survivor function. The life-table method requires a fairly large number of observations so that survival times can be grouped into intervals. These are specified using the INTERVALS option. For equal intervals, you can set INTERVALS to a scalar to define their width. Alternatively you can set INTERVALS to a variate containing the lower boundaries of the intervals. The PLOT option can be used to produce plots of the survivor function (survivor), estimated hazard function (hazard) and the probability density function (pdf). You can set the option PRINT=* to suppress printing of the life table; by default PRINT=lifetable.

   The observed timepoints (or the timepoints at which censoring took place) are specified using the TIMES parameter. The CENSORED parameter specifies a variate containing the value one if the corresponding element of TIMES is censored or zero if it was not. CENSORED can be omitted if there was no censoring. If there are several observations (all censored or all uncensored) at a time point, you can specify the time point only once and define the number of observations by specifying a variate of counts using the FREQUENCY parameter. This is particularly useful if the contents of the TIMES variate are intended to identify time intervals rather than discrete time points. The GROUPS parameter can be used to request separate life tables for different groups of data. The LIFETABLE parameter allows the life table to be saved in a pointer to a set of variates for each of the columns within the table.

 

Options: PRINT, PLOT, INTERVAL.

Parameters: TIMES, CENSORED, FREQUENCY, GROUPS, LIFETABLE.


Method

The methodology in RLIFETABLE is based on that described in Chapter 4 of Lee (1992).


Action with RESTRICT

The input variates and factors may be restricted identically. The life tables are based only on the units not excluded by the restriction.


Reference

Lee, E.T. (1992). Statistical Methods for Survival Data Analysis. Wiley, New York.