The ODS Graphics plot produced by the PLOTS=PROBPLOT option on the PROC LIFEREG statement is incorrect. The data to compute the Kaplan-Meier estimates (points on the plot) are not sorted first.

The probabilty plots produced by the PROBPLOT statement are correct and serve as a workaround.

Operating System and Release Information

Product Family	Product	System	SAS Release
			Reported	Fixed*
SAS System	SAS/STAT	z/OS	9.2 TS1M0	9.4 TS1M0
		Microsoft® Windows® for 64-Bit Itanium-based Systems	9.2 TS1M0
		Microsoft Windows Server 2003 Datacenter 64-bit Edition	9.2 TS1M0
		Microsoft Windows Server 2003 Enterprise 64-bit Edition	9.2 TS1M0
		Microsoft Windows XP 64-bit Edition	9.2 TS1M0
		Microsoft® Windows® for x64	9.2 TS1M0	9.4 TS1M0
		Microsoft Windows Server 2003 Datacenter Edition	9.2 TS1M0
		Microsoft Windows Server 2003 Enterprise Edition	9.2 TS1M0
		Microsoft Windows Server 2003 Standard Edition	9.2 TS1M0
		Microsoft Windows XP Professional	9.2 TS1M0
		Windows Vista	9.2 TS1M0
		Windows Vista for x64	9.2 TS1M0
		64-bit Enabled AIX	9.2 TS1M0	9.4 TS1M0
		64-bit Enabled HP-UX	9.2 TS1M0	9.4 TS1M0
		64-bit Enabled Solaris	9.2 TS1M0	9.4 TS1M0
		HP-UX IPF	9.2 TS1M0	9.4 TS1M0
		Linux	9.2 TS1M0	9.4 TS1M0
		Linux for x64	9.2 TS1M0	9.4 TS1M0
		OpenVMS on HP Integrity	9.2 TS1M0	9.4 TS1M0
		Solaris for x64	9.2 TS1M0	9.4 TS1M0

* For software releases that are not yet generally available, the Fixed Release is the software release in which the problem is planned to be fixed.

The code below illustrates using the PROBPLOT statement (produces correct pplot) and the PLOTS=PROBPLOT option on the PROC LIFEREG statement (produces incorrect pplot). The use of the PROBPLOT statement serves as a workaround here.

---

data Headache;
     input Minutes Group Censor @@;
     datalines;
     11  1  0   12  1  0   19  1  0   19  1  0
     19  1  0   19  1  0   21  1  0   20  1  0
     21  1  0   21  1  0   20  1  0   21  1  0
     20  1  0   21  1  0   25  1  0   27  1  0
     30  1  0   21  1  1   24  1  1   14  2  0
     16  2  0   16  2  0   21  2  0   21  2  0
     23  2  0   23  2  0   23  2  0   23  2  0
     25  2  1   23  2  0   24  2  0   24  2  0
     26  2  1   32  2  1   30  2  1   30  2  0
     32  2  1   20  2  1
     ;


ods graphics on;

/* correct pplot with PROBPLOT statement */
ods select ProbPlot;
proc lifereg data=Headache;
     class Group;
     model Minutes*Censor(1) = Group / dist=Weibull;
     probplot;
     title1 "Case 1:  PROBPLOT statement (only)";
     run;

/* incorrect pplot with PLOTS=PROBPLOT option */
ods select ProbPlot;
proc lifereg data=Headache plots=probplot;
     class Group;
     model Minutes*Censor(1) = Group / dist=Weibull;
     title1 "Case 2:  PLOTS=PROBPLOT option (only)";
     run;

ods graphics off;

Type:	Problem Note
Priority:	alert
Topic:	Analytics ==> Reliability Analysis Analytics ==> Survival Analysis

Date Modified:	2025-06-27 15:56:01
Date Created:	2012-09-28 07:00:15