PROC LIFETEST passes to the survival plots a number of dynamic variables that contain summary statistics. Some of these dynamic variables are used when you call the %SurvivalSummaryTable macro. Table 23.1 and Table 23.2 list these additional dynamic variables for the Kaplan-Meier curves and the life-table curves, respectively. These dynamic variables are not declared in the templates for the survival curves, but you can declare them and use them to enhance the default plots.[21] The names of the dynamic variables depend on the STRATA= suboption of the PLOTS=SURVIVAL option: STRATA=INDIVIDUAL produces a separate plot for each stratum, and STRATA=OVERALL produces one plot that has overlaid curves.
Table 23.1: Additional Dynamic Variables for Stat.Graphics.ProductLimitSurvival
|
STRATA= |
Dynamic |
Description |
|---|---|---|
|
OVERLAY |
|
Label for the jth stratum |
|
|
Number of observations in the jth stratum |
|
|
|
Number of events in the jth stratum |
|
|
|
Median survival time of the jth stratum |
|
|
|
Lower median survival time of the jth stratum |
|
|
|
Upper median survival time of the jth stratum |
|
|
|
Confidence of the median intervals, in percentage |
|
|
INDIVIDUAL |
|
Number of observations |
|
|
Number of events |
|
|
|
Median survival time |
|
|
|
Lower median survival time |
|
|
|
Upper median survival time |
|
|
|
Confidence of the median intervals, in percentage |
Table 23.2: Additional Dynamic Variables for Stat.Graphics.LifetableSurvival
|
STRATA= |
Dynamic |
Description |
|---|---|---|
|
OVERLAY |
|
Label for the jth stratum |
|
|
Number of observations in the jth stratum |
|
|
|
Number of events in the jth stratum |
|
|
INDIVIDUAL |
|
Number of observations |
|
|
Number of events |
[21] Because the number of dynamic variables is a function of the number of strata, the template definition cannot automatically contain the correct number of dynamic variables.