Problem Note 49838: TWOSAMPLESURVIVAL statement options EVENTSPERGROUP=, GROUPEVENTS=, and EVENTSTOTAL= produce incorrect results
In SAS 9.3 TS1M0 and SAS 9.3 TS1M1, the EVENTSPERGROUP= and GROUPEVENTS= options in the TWOSAMPLESURVIVAL statement in PROC POWER produce incorrect results. In addition, the power computed from the EVENTSTOTAL= option is incorrect. This surfaces both when solving for POWER (computed Power is wrong) and when solving for EVENTSTOTAL (the computed Event Total values are correct, but the computed Actual Power value is incorrect).
As a workaround, do not specify the EVENTSPERGROUP=, GROUPEVENTS= or EVENTSTOTAL= options. You should instead use another sample size specification and allocation method available in the TWOSAMPLESURVIVAL statement. Note that in SAS 9.3 TS1M2 (SAS/STAT 12.1), the EVENTSPERGROUP= and GROUPEVENTS= options have been removed from the procedure. Also, the computations for Power and Acual Power in the EVENTSTOTAL= option have been corrected.
Operating System and Release Information
| SAS System | SAS/STAT | z/OS | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| Microsoft® Windows® for x64 | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| Microsoft Windows Server 2003 Datacenter Edition | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| Microsoft Windows Server 2003 Enterprise Edition | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| Microsoft Windows Server 2003 Standard Edition | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| Microsoft Windows Server 2003 for x64 | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| Microsoft Windows Server 2008 | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| Microsoft Windows Server 2008 for x64 | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| Microsoft Windows XP Professional | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| Windows 7 Enterprise 32 bit | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| Windows 7 Enterprise x64 | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| Windows 7 Home Premium 32 bit | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| Windows 7 Home Premium x64 | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| Windows 7 Professional 32 bit | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| Windows 7 Professional x64 | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| Windows 7 Ultimate 32 bit | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| Windows 7 Ultimate x64 | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| Windows Vista | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| Windows Vista for x64 | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| 64-bit Enabled AIX | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| 64-bit Enabled HP-UX | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| 64-bit Enabled Solaris | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| HP-UX IPF | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| Linux | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| Linux for x64 | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
| Solaris for x64 | 9.3 | 12.1 | 9.3 TS1M1 | 9.3 TS1M2 |
*
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.
| Type: | Problem Note |
| Priority: | high |
| Topic: | Analytics ==> Power and Sample Size
SAS Reference ==> Procedures ==> POWER
|
| Date Modified: | 2013-08-12 16:42:26 |
| Date Created: | 2013-05-02 10:53:33 |
