TITLE:      LGM with categorical outcomes: Delta parameterization 

DATA:       File is Duncan_101.dat;

VARIABLE:   Names are Y1 Y2 Y3 Y4; 
            Usevar =  Y1-Y4;
            Categorical are Y1-Y4;

ANALYSIS:  !model=nomeanstructure;

MODEL:      i BY Y1-Y4@1;
            s BY Y1@0 Y2@1 Y3@2 y4@3;
            [Y1$1 Y2$1 Y3$1 Y4$1] (T1);!thresholds held equal across time points
            [Y1$2 Y2$2 Y3$2 Y4$2] (T2);
            {y1@1.0 y2* y3* y4*}; !differences in variances of the outcome over time
            !are represented by allowing scale parameters to vary over time

OUTPUT:     tech1 tech3 tech4 sampstat standardized;