DOMAIN Statement

The SURVEYMEANS Procedure

DOMAIN Statement

DOMAIN $\, | \,$ SUBGROUP variables < variable*variable variable*variable*variable ... > ;

The DOMAIN statement requests analysis for subpopulations, or domains, in addition to analysis for the entire study population. The DOMAIN statement names the variables that identify domains, which are called domain variables. It is common practice to compute statistics for domains. The formation of these domains may be unrelated to the sample design. Therefore, the sample sizes for the domains are random variables. In order to incorporate this variability into the variance estimation, you should use a DOMAIN statement.

Note that a DOMAIN statement is different from a BY statement. In a BY statement, you treat the sample sizes as fixed in each subpopulation, and you perform analysis within each BY group independently. See the section "Domain Analysis" for more details.

A domain variable can be either character or numeric. However, the procedure treats domain variables as categorical variables. If a variable appears by itself in a DOMAIN statement, each level of this variable determines a domain in the study population. If two or more variables are joined by asterisks (*), then every possible combination of levels of the variables determines a domain. The procedure performs a descriptive analysis within each domain defined by the domain variables.

The formatted values of the domain variables determine the categorical variable levels. Thus, you can use formats to group values into levels. Refer to the discussion of the FORMAT procedure in the SAS Procedures Guide and to the discussions of the FORMAT statement and SAS formats in SAS Language Reference: Dictionary.

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