You can specify a BY statement with the GLMMOD procedure to obtain
separate designs for observations in groups defined by the BY
variables. When you specify a BY statement, the procedure expects
the input DATA= data set to be sorted in the order of the BY
- BY variables ;
If your input data set is not sorted in ascending order, use
one of the following alternatives:
- Sort the data using the SORT procedure with a similar
- Specify the BY statement option NOTSORTED or DESCENDING
in the BY statement for the GLMMOD procedure.
The NOTSORTED option does not mean that the data are
unsorted but rather that the data are arranged in
groups (according to values of the BY variables)
and that these groups are not necessarily in
alphabetical or increasing numeric order.
- Create an index on the BY variables using the DATASETS procedure
(in base SAS software).
For more information on the BY statement, refer to the discussion
in SAS Language Reference: Concepts.
For more information on the DATASETS procedure, refer to the
discussion in the SAS Procedures Guide.
Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.