PROC SURVEYMEANS - Domain & Class Statements

[_maldini_]

I'm trying to use PROC SURVEYMEANS to analyze continuous variables from a weighted survey (i.e., NHANES). This article has been helpful.

I want to look at age (continuous) by year, in a subpopulation defined by a flag variable (i.e., flag_1).

proc surveymeans DATA=nhanes.go nomcar;
 	STRATUM sdmvstra;
 	CLUSTER sdmvpsu;
 	WEIGHT wtmec10yr_09_18;
 	
/* DOMAIN: used instead of the WHERE or BY statement to provide analyses of subgroups.  */
	domain flag_1 year;
	var age_yrs;
run; 

When both flag_1 and year are included in the DOMAIN statement, I get the mean of age_yrs by flag_1 (0, 1) and by year, but not by both (see screenshot). 

I am seeking the mean of age_yrs by year when flag_1 = 1.

I've tried adding a CLASS statement to no avail.

Thanks for any suggestions.

[ballardw · Accepted solution]

From the documentation:

If two or more variables are joined by asterisks (*), then every possible combination of levels of these variables determines a domain

If you use this you should get the desired result.

Domain flag_1 * year;

If you want the individual domains and the combined use:

Domain flag_1 * year   flag_1  year;