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The LIFETEST Procedure

ODS Graphics

To request graphics with PROC LIFETEST, you must first enable ODS Graphics by specifying the ods graphics on statement. See Chapter 21, Statistical Graphics Using ODS, for more information. The survival plot is produced by default; other graphs are produced by using the PLOTS= option in the PROC LIFETEST statement. You can reference every graph produced through ODS Graphics with a name. The names of the graphs that PROC LIFETEST generates are listed in Table 49.5, along with the required keywords for the PLOTS= option.

Table 49.5 ODS Graphics Produced by PROC LIFETEST

ODS Graph Name

Plot Description

PLOTS=Option

DensityPlot

Estimated density for life-table method

PDF

FailurePlot

Estimated failure function

SURVIVAL(FAILURE)

HazardPlot

Estimated hazard function for life-table method or smoothed hazard for product-limit method

HAZARD

LogNegLogSurvivalPlot

Log of negative log of the estimated survivor function

LOGLOGS

NegLogSurvivalPlot

Negative log of the estimated survivor function

LOGSURV

SurvivalPlot

Estimated survivor function

SURVIVAL

SurvivalPlot

Estimated survivor function with number of subjects at risk

SURVIVAL(ATRISK=)

SurvivalPlot

Estimated survivor function with pointwise confidence limits

SURVIVAL(CL)

SurvivalPlot

Estimated survivor function with equal-precision band

SURVIVAL(CB=EP)

SurvivalPlot

Estimated survivor function with Hall-Wellner band

SURVIVAL(CB=HW)

SurvivalPlot

Estimated survivor function with homogeneity test p-value

SURVIVAL(TEST)

Additional Dynamic Variables for Survival Plots Using ODS Graphics

PROC LIFETEST passes a number of summary statistics as dynamic variables to the ODS Graphics for survival plots. Table 49.6 and Table 49.7 list these additional dynamic variables for the Kaplan-Meier 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. 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 with overlaid curves.

Table 49.6 Additional Dynamic Variables for Stat.Graphics.ProductLimitSurvival

STRATA=

Dynamic

Description

OVERLAY

StrVal

Label for the th stratum

 

NObs

Number of observations in the th stratum

 

NEvent

Number of events in the th stratum

 

Median

Median survival time of the th stratum

 

LowerMedian

Lower median survival time of the th stratum

 

UpperMedian

Upper median survival time of the th stratum

 

pctMedianConfid

Percent confidence of the median intervals

INDIVIDUAL

NObs

Number of observations

 

NEvent

Number of events

 

Median

Median survival time

 

LowerMedian

Lower median survival time

 

UpperMedian

Upper median survival time

 

pctMedianConfid

Percent confidence of the median interval

Table 49.7 Additional Dynamic Variables for Stat.Graphics.LifetableSurvival

STRATA=

Dynamic

Description

OVERLAY

StrVal

Label for the th stratum

 

NObs

Number of observations in the th stratum

 

NEvent

Number of events in the th stratum

INDIVIDUAL

NObs

Number of observations

 

NEvent

Number of events

See the section The Graph Template Language and Example 21.5 in Chapter 21, Statistical Graphics Using ODS, for more information about dynamic variables and ODS Graphics.

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