The CLASS statement names the classification variables to be used in the analysis. If the CLASS statement is used, it must appear before the MODEL statement.

Classification variables can be either character or numeric. By default, class levels are determined from the entire formatted values of the CLASS variables. Note that this represents a slight change from previous releases in the way in which class levels are determined. Prior to SAS 9, class levels were determined by using no more than the first 16 characters of the formatted values. If you want to revert to this previous behavior, you can use the TRUNCATE option in the CLASS statement. In any case, you can use formats to group values into levels. See the discussion of the FORMAT procedure in the Base SAS Procedures Guide and the discussions of the FORMAT statement and SAS formats in SAS Language Reference: Dictionary.

Any variable in the model that is not listed in the CLASS statement is assumed to be continuous. Continuous variables must be numeric.

You can specify the following option in the CLASS statement after a slash(/):