LMIXED Procedure
CLASS Statement
CLASS variable <(options)>
<variable <(options)>> </ global-options>;
The CLASS statement names the classification variables to be used as explanatory variables in the analysis. Table 3 summarizes the values that you can use as either an option or a global-option. The options are fully documented in the section CLASS Statement (SAS Visual Statistics: Procedures) in Chapter 2, Shared Concepts (SAS Visual Statistics: Procedures).
Table 3: CLASS Statement Options
| Option | Description |
|---|---|
| DESCENDING | Reverses the sort order |
| MISSING | Treats missing values as valid levels |
| ORDER= | Specifies the sort order for the levels |
| PARAM= | Specifies the parameterization of the variable |
| REF= | Specifies the reference level of the variable and puts this level at the end of the list of levels. This interpretation of the specified REF= level does not apply when DMMETHOD=SPARSE, because in this case PROC LMIXED does not necessarily solve mixed model equations in the original order. |
Note that the term 'INTERCEPT' is reserved as a keyword in several statements in PROC LMIXED. Therefore, you cannot use it it as a classification variable name in the CLASS statement.
Last updated: May 14, 2026