Hi, I have an animal study where I am interested in statistically controlling for parentage among my subjects. I have DAM_ID and SIRE_ID as nominal variables, and I *think* the following syntax is right (I use SPSS v.30):

MIXED outcome BY sex group with covariate1 covariate2

/FIXED=sex group sex*group covariate1 covariate2 | SSTYPE(3)

/METHOD=REML

/PRINT= CORB COVB SOLUTION TESTCOV

/RANDOM=intercept | subject (DAM_ID SIRE_ID).

So, I am interested in whether my outcome measure is influenced by sex, group, and their interaction, after controlling for the two covariates and parentage. FYI, the data set contains 2340 cases, and females have up to 6 offspring represented in the database, while males have up to 54 offspring (though for both dams and sires, the modal number of offspring in the database is 1).

The syntax does give me an output (ie, SPSS does not crash), but I want to be sure I am specifying parentage correctly. Any suggestions? And thanks.