Give a label to the loading you want to vary with age, say "load". Then say
Model Constraint: New(a b); load = a + b*age;
This way the loading is a linear function of age.
JackeJR posted on Wednesday, May 11, 2016 - 12:05 am
Thanks Dr Muthen. Just to clarify, I run
VARIABLE: CONSTRAINT = AGE
MODEL: f1 BY y1-y4; f2 BY y5-y8; f3 BY y9-y12; f1-f3(load);
MODEL CONSTRAINT New(a b); load = a + b*AGE;
A significant "b" suggests that age predicts the factor loading? or should I be comparing the model with constraints with the one without constraints to see if adding the constraints improve model fit?