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 KaplanMeier curves and the lifetable 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.