Problem Note 62723: PROC LIFETEST reports incorrect survival results when the TIMELIST= includes zero and there is an event at time zero
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If you include zero in the TIMELIST= option in PROC LIFETEST and an event occurs at time zero, the first row in the Product-Limit Survival Estimates table is incorrect. The results indicate that the survival function estimate is 1 and the number of failures is 0.
Here is an example using fictitious data that demonstrates the problem:
data test;
input Days Event;
datalines;
0 1
5 1
9 1
16 0
20 1
20 1
22 0
25 1
;
proc lifetest data=test timelist=0 5 10 15 20 25;
time days*event(0);
run;
input Days Event;
datalines;
0 1
5 1
9 1
16 0
20 1
20 1
22 0
25 1
;
proc lifetest data=test timelist=0 5 10 15 20 25;
time days*event(0);
run;
The Product-Limit Survival Estimates table is:
The correct survival estimate at 0 days for this example is 0.8750. This can be obtained, as well as correct values for the number of failures, standard error, number failed and number left, by omitting the TIMELIST= option.
Operating System and Release Information
| Product Family | Product | System | Product Release | SAS Release | ||
| Reported | Fixed* | Reported | Fixed* | |||
| SAS System | SAS/STAT | z/OS | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 |
| z/OS 64-bit | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Microsoft® Windows® for x64 | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Microsoft Windows 8 Enterprise 32-bit | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Microsoft Windows 8 Enterprise x64 | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Microsoft Windows 8 Pro 32-bit | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Microsoft Windows 8 Pro x64 | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Microsoft Windows 8.1 Enterprise 32-bit | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Microsoft Windows 8.1 Enterprise x64 | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Microsoft Windows 8.1 Pro 32-bit | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Microsoft Windows 8.1 Pro x64 | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Microsoft Windows 10 | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Microsoft Windows Server 2008 | 14.3 | 9.4 TS1M5 | ||||
| Microsoft Windows Server 2008 R2 | 14.3 | 9.4 TS1M5 | ||||
| Microsoft Windows Server 2008 for x64 | 14.3 | 9.4 TS1M5 | ||||
| Microsoft Windows Server 2012 Datacenter | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Microsoft Windows Server 2012 R2 Datacenter | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Microsoft Windows Server 2012 R2 Std | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Microsoft Windows Server 2012 Std | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Microsoft Windows Server 2016 | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Windows 7 Enterprise 32 bit | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Windows 7 Enterprise x64 | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Windows 7 Home Premium 32 bit | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Windows 7 Home Premium x64 | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Windows 7 Professional 32 bit | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Windows 7 Professional x64 | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Windows 7 Ultimate 32 bit | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Windows 7 Ultimate x64 | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| 64-bit Enabled AIX | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| 64-bit Enabled Solaris | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| HP-UX IPF | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Linux for x64 | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
| Solaris for x64 | 14.3 | 15.1 | 9.4 TS1M5 | 9.4 TS1M6 | ||
In SAS 9.4 TS1M5 (SAS/STAT 14.3), the time 0 survival results are incorrect in PROC LIFETEST if there is an event at time 0 and the TIMELIST= option includes 0.
| Type: | Problem Note |
| Priority: | high |
| Topic: | Analytics ==> Survival Analysis SAS Reference ==> Procedures ==> LIFETEST |
| Date Modified: | 2019-01-24 11:21:51 |
| Date Created: | 2018-08-07 14:57:28 |