The LIFETEST Procedure

Plot Options Superseded by ODS Graphics

You can select one of the following three types of graphics in PROC LIFETEST: ODS, traditional, and line printer. ODS Graphics is the preferred method of creating graphs, superseding the other two.

When ODS Graphics is enabled, you can use the PLOTS= option in the PROC LIFETEST statement to create plots by using ODS Graphics. For more information about ODS Graphics options see the PLOTS= option in the section PROC LIFETEST Statement.

If ODS Graphics is not enabled and you specify the LINEPRINTER option, line printer plots are produced; otherwise traditional graphics are produced.

Table 58.4 summarizes the ways in which you can request graphics.

Table 58.4: Ways of Displaying Graphics

		PLOTS=	LINEPRINTER
Graphics Result	ODS Graphics	Option Specified?	Option Specified?
ODS Graphics	Enabled	Yes	No
ODS Graphics survival plot	Enabled	No	No
Traditional graphics	Disabled	Yes	No
Line printer plot	Enabled	Yes	Yes
Line printer plot	Disabled	Yes	Yes
No graphics	Disabled	No	No
No graphics	Disabled	No	Yes
No graphics	Enabled	No	Yes

Table 58.5 summarizes the options available in the PROC LIFETEST statement for line printer and traditional graphics.

Table 58.5: Line Printer and Traditional Graphics Options Available in the PROC LIFETEST Statement

Option	Description
Line Printer Plots
FORMCHAR(1,2,7,9)=	Defines the characters to be used for line printer plot axes
LINEPRINTER	Specifies that plots be produced by a line printer
MAXTIME=	Specifies the maximum time value for plotting
NOCENSPLOT	Suppresses the plot of censored observations
PLOTS=	Specifies the plots to display
Traditional Graphics
ANNOTATE=	Specifies an Annotate data set that adds features to plots
CENSOREDSYMBOL=	Defines the symbol to be used for censored observations in plots
DESCRIPTION=	Specifies the string that appears in the description field of the PROC GREPLAY master menu for the plots
EVENTSYMBOL=	Specifies the symbol to be used for event observations in plots
GOUT=	Specifies the graphics catalog name for saving graphics output
LANNOTATE=	Specifies an input data set that contains variables for local annotation
MAXTIME=	Specifies the maximum time value for plotting
PLOTS=	Specifies the plots to display

The following options are used to produce line printer and traditional graphics:

ANNOTATE=SAS-data-set ANNO=SAS-data-set

specifies an input data set that contains appropriate variables for annotation of the traditional graphics. The ANNOTATE= option enables you to add features (for example, labels that explain extreme observations) to plots produced on graphics devices. The ANNOTATE= option cannot be used if the LINEPRINTER option is specified or if ODS Graphics is enabled. The data set specified must be an ANNOTATE= type data set, as described in SAS/GRAPH: Reference.

The data set specified with the ANNOTATE= option in the PROC LIFETEST statement is "global" in the sense that the information in this data set is displayed in every plot produced by a single invocation of PROC LIFETEST.

CENSOREDSYMBOL=name | ’string’ CS=name | ’string’

specifies the symbol value for the censored observations in traditional graphics. The value, name or ’string’, is the symbol value specification allowed in SAS/GRAPH software. The default is CS=CIRCLE. If you want to omit plotting the censored observations, specify CS=NONE. The CENSOREDSYMBOL= option cannot be used if the LINEPRINTER option is specified or if ODS Graphics is enabled.

DESCRIPTION='string' DES='string'

specifies a descriptive string of up to 256 characters that appears in the "Description" field of the traditional graphics catalog. The description does not appear in the plots. By default, PROC LIFETEST assigns a description of the form PLOT OF vname versus hname, where vname and hname are the names of the y variable and the x variable, respectively. The DESCRIPTION= option cannot be used if the LINEPRINTER option is specified or if ODS Graphics is enabled.

EVENTSYMBOL=name | 'string' ES=name | 'string'

specifies the symbol value for the event observations in traditional graphics. The value, name or ’string’, is the symbol value specification allowed in SAS/GRAPH software. The default is ES=NONE. The EVENTSYMBOL= option cannot be used if the LINEPRINTER option is specified or if ODS Graphics is enabled.

FORMCHAR(1,2,7,9)=’string’

defines the characters to be used for constructing the vertical and horizontal axes of the line printer plots. The string should be four characters. The first and second characters define the vertical and horizontal bars, respectively, which are also used in drawing the steps of the Kaplan-Meier, Breslow, or Fleming-Harrington survival curve. The third character defines the tick mark for the axes, and the fourth character defines the lower left corner of the plot. The default is FORMCHAR(1,2,7,9)='|-+-'. Any character or hexadecimal string can be used to customize the plot appearance. If you use hexadecimals, you must put an x after the closing quote. For example, to send the plot output to a printer with the IBM graphics character set (1 or 2), specify the following:

formchar(1,2,7,9)='B3C4C5C0'x

See the chapter titled "The PLOT Procedure" in the Base SAS Procedures Guide for further information.

GOUT=graphics-catalog

specifies the graphics catalog for saving traditional graphics output from PROC LIFETEST. The default is Work.Gseg. The GOUT= option cannot be used if the LINEPRINTER option is specified or if ODS Graphics is enabled. For more information, see the chapter titled "The GREPLAY Procedure" in SAS/GRAPH: Reference.

LANNOTATE=SAS-data-set LANN=SAS-data-set

specifies an input data set that contains variables for local annotation of traditional graphics. You can use the LANNOTATE= option to specify a different annotation for each BY group, in which case the BY variables must be included in the LANNOTATE= data set. The LANNOTATE= option cannot be used if the LINEPRINTER option is specified or if ODS Graphics is enabled. The data set specified must be an ANNOTATE= type data set, as described in SAS/GRAPH: Reference.

If there is no BY-group processing, the ANNOTATE= and LANNOTATE= options have the same effects.

LINEPRINTER LS

specifies that plots are produced by a line printer instead of by a graphical device.

MAXTIME=value

specifies the maximum value of the time variable allowed on the plots so that outlying points do not determine the scale of the time axis of the plots. This option affects only the displayed plots and has no effect on any calculations.

NOCENSPLOT NOCENS

requests that the plot of censored observations be suppressed when the LINEPRINTER and PLOTS= options are specified. This option is not needed when the life-table method is used to compute the survival estimates, because the plot of censored observations is not produced.

Line Printer PLOTS= Option

PLOTS=plot-request PLOTS=(plot-requests)

controls the line printer plots produced. You must also specify the LINEPRINTER option to obtain line printer plots. When you specify only one plot-request, you can omit the parentheses around the plot-request. Here are some examples:

 plots=s
 plots=(s ls lls)

The plot-requests include the following:

CENSORED C: specifies a plot of censored observations. This option is available for METHOD=KM, METHOD=BRESLOW, or METHOD=FH only.
SURVIVAL S: specifies a plot of the estimated SDF versus time.
LOGSURV LS: specifies a plot of the negative log of the estimated SDF versus time.
LOGLOGS LLS: specifies a plot of the log of the negative log of the estimated SDF versus the log of time.
HAZARD H: specifies a plot of the estimated hazard function versus time (life-table method only).
PDF P: specifies a plot of the estimated probability density function versus time (life-table method only).

Traditional Graphics PLOTS= Option

PLOTS=plot-request <(NAME=name | ’string’)> PLOTS=(plot-request <(NAME=name | ’string’)> <, …, plot-request <(NAME=name | ’string’)> >)

controls plots produced in traditional graphics. To obtain traditional graphics, you must neither enable ODS Graphics nor specify the LINEPRINTER option. For each plot-request, you can use the NAME= option to specify a name to identify the plot. The name can be specified as a SAS name or as a quoted string of up to 256 characters. Only the first eight characters are used as the entry name in the GOUT= catalog. The plot-requests include the following:

SURVIVAL S: plots the estimated survivor functions versus time.
LOGSURV LS: plots the negative log of estimated survivor functions versus time.
LOGLOGS LLS: plots the log of negative log of estimated survivor functions versus the log of time.
HAZARD H: plots estimated hazard function versus time (life-table method only).
PDF P: plots the estimated probability density function versus time (life-table method only).

When you specify only one plot-request, you can omit the parentheses around the plot-request. Here are some examples:

 plots=s
 plots=(s(name=Surv2), h(name=Haz2))

The latter requests a plot of the estimated survivor function versus time and a plot of the estimated hazard function versus time, with Surv2 and Haz2 as their names in the GOUT= catalog, respectively.