Problem Note 36072: ADJUST=DUNNETT DIFF=CONTROL does not always use the specified control level and may cause a Read Access Violation error
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The ADJUST=DUNNETT DIFF=CONTROL(...) options on the STRATA statement in PROC LIFETEST do not always use the specified control level.
For unstratified k-sample tests (when the GROUP= option is NOT specified), the control level for the Dunnett multiple comparisons specified in DIFF=CONTROL(...) works correctly if there is only one STRATA variable. If there are two or more STRATA variables, only the first STRATA variable is used; that is, the first stratum that matches the first specified string in DIFF=CONTROL(...) is used as the control.
For stratified tests (where the GROUP= option is specified), there are two scenarios:
1) If the number of groups is less than or equal to the number of strata, the control level is always the first group regardless of what is specified in DIFF=CONTROL(...).
2) If the number of groups is larger than the number of strata, this will result in a Read Access Violation error and possibly freeze up the SAS session.
Since the default is to use the first stratum or group, the workaround is to use the default, e.g. - DIFF=CONTROL, and a format that designates the control as the first stratum or group.
Operating System and Release Information
| Product Family | Product | System | SAS Release | |
| Reported | Fixed* | |||
| SAS System | SAS/STAT | z/OS | 9.2 TS1M0 | 9.2 TS2M2 |
| Microsoft® Windows® for 64-Bit Itanium-based Systems | 9.2 TS1M0 | 9.2 TS2M2 | ||
| Microsoft Windows Server 2003 Datacenter 64-bit Edition | 9.2 TS1M0 | 9.2 TS2M2 | ||
| Microsoft Windows Server 2003 Enterprise 64-bit Edition | 9.2 TS1M0 | 9.2 TS2M2 | ||
| Microsoft Windows XP 64-bit Edition | 9.2 TS1M0 | 9.2 TS2M2 | ||
| Microsoft® Windows® for x64 | 9.2 TS1M0 | 9.2 TS2M2 | ||
| Microsoft Windows Server 2003 Datacenter Edition | 9.2 TS1M0 | 9.2 TS2M2 | ||
| Microsoft Windows Server 2003 Enterprise Edition | 9.2 TS1M0 | 9.2 TS2M2 | ||
| Microsoft Windows Server 2003 Standard Edition | 9.2 TS1M0 | 9.2 TS2M2 | ||
| Microsoft Windows XP Professional | 9.2 TS1M0 | 9.2 TS2M2 | ||
| Windows Vista | 9.2 TS1M0 | 9.2 TS2M2 | ||
| 64-bit Enabled AIX | 9.2 TS1M0 | 9.2 TS2M2 | ||
| 64-bit Enabled HP-UX | 9.2 TS1M0 | 9.2 TS2M2 | ||
| 64-bit Enabled Solaris | 9.2 TS1M0 | 9.2 TS2M2 | ||
| HP-UX IPF | 9.2 TS1M0 | 9.2 TS2M2 | ||
| Linux | 9.2 TS1M0 | 9.2 TS2M2 | ||
| Linux for x64 | 9.2 TS1M0 | 9.2 TS2M2 | ||
| OpenVMS on HP Integrity | 9.2 TS1M0 | 9.2 TS2M2 | ||
| Solaris for x64 | 9.2 TS1M0 | 9.2 TS2M2 | ||