PROC LIFETEST
<options> ;
The PROC LIFETEST statement invokes the LIFETEST procedure. Optionally, this statement identifies an input and an OUTSURV= data set, and specifies the computation details of the survivor function estimation. Table 52.1 summarizes the options available in the PROC LIFETEST statement. These options are described in alphabetic order. If no options are requested, PROC LIFETEST computes and displays the productlimit estimate of the survivor function; and if ODS Graphics is enabled, a plot of the estimated survivor function is also displayed.
Table 52.1: Options Available in the PROC LIFETEST Statement
Option 
Description 

Input and Output Data Sets 

Specifies the input SAS data set 

Names an output data set to contain survival estimates and confidence limits 

Names an output data set to contain rank test statistics for association of survival time with covariates 

Nonparametric Estimation 

Specifies interval endpoints for lifetable estimates 

Adds the NelsonAalen estimates 

Specifies the method to compute survivor function 

Specifies the number of intervals for lifetable estimates 

Specifies the width of intervals for lifetable estimates 

Confidence Limits for Survivorship 

Sets the confidence level for interval estimation estimates 

Specifies the maximum time for confidence band 

Specifies the minimum time for confidence band 

Specifies the type of confidence band in the OUTSURV= data set 

Specifies the transformation applied to the survivor function to obtain confidence limits 

Line Printer Plots 

Defines the characters used for line printer plot axes 

Specifies that plots be produced by a line printer 

Specifies the maximum time value for plotting 

Suppresses the plot of censored observations 

Specifies the plots to display 

ODS Graphics 

Specifies the maximum time value for plotting 

Specifies plots to display 

Traditional Graphics 

Specifies an Annotate data set that adds features to plots 

Defines the symbol used for censored observations in plots 

Specifies the string that appears in the description field of the PROC GREPLAY master menu for the plots 

Specifies the symbol used for event observations in plots 

Specifies the graphics catalog name for saving graphics output 

Specifies an input data set that contains variables for local annotation 

Specifies the maximum time value for plotting 

Specifies the plots to display 

Control Output 

Adds the number of subjects at risk to the survival estimate table 

Suppresses the display of printed output 

Suppresses the display of survival function estimates 

Displays only the estimate for the smallest time in each interval 

Suppresses the Number Left column in the survival estimate table 

Specifies a list of time points to display the survival estimate 

Specifies that only INTERVAL= or TIMELIST= observations be listed in the OUTSURV= data set 

Miscellaneous 

Sets the confidence level for survival time quartiles 

Allows missing values to be a stratum level 

Sets the tolerance for testing singularity of covariance matrix of rank statistics 

Outputs the standard error for the survival estimators to the OUTSURV= data set 

Specifies the time limit used to estimate the mean survival time and its standard error 
The PLOTS= option in the PROC LIFETEST statement specifies the plots to display. You can select one of the following three types of graphics in PROC LIFETEST: line printer, traditional, and ODS. If you specify the LINEPRINTER option, line printer plots are produced; otherwise traditional graphics are produced if ODS Graphics is not enabled, or ODS Graphics plots are produced if the ODS Graphics is enabled.
For more information about enabling and disabling ODS Graphics, see the section Enabling and Disabling ODS Graphics in Chapter 21: Statistical Graphics Using ODS.
Table 52.2 shows whether graphics are produced, and the type of graphics, for all possible combinations:
Table 52.2: Ways of Displaying Graphics
ODS Graphics 
PLOTS= Option 
LINEPRINTER Option 
Graphics Results 

Disabled 
No 
No 
No graphics 
Disabled 
No 
Yes 
No graphics 
Disabled 
Yes 
No 
Traditional graphics 
Disabled 
Yes 
Yes 
Line printer plot 
Enabled 
No 
No 
ODS Graphics survival plot 
Enabled 
No 
Yes 
No graphics 
Enabled 
Yes 
No 
ODS Graphics 
Enabled 
Yes 
Yes 
Line printer plot 
ODS Graphics is the preferred method of creating graphs. Many new features have been added to the ODS Graphics plots in PROC LIFETEST. For example, you can display the number of subjects at risk in a survival plot through ODS Graphics, but such a feature is not available in traditional graphics or line printer plots. The PLOTS= option syntax is documented separately for each type of graphics and is preceded by a heading that indicates the graphics type.
Line Printer PLOTS= Option
ODS Graphics PLOTS= Option
Traditional Graphics PLOTS= Option