Dear all,
When estimating a SEM with categorical variables using, can we constrain the intervals between thresholds? For instance in this simple model with the latent variable A and two indicator A1 and A2:
A =~ A1 + A2
A1 | a1*t1 + a2*t2 + a3*t3 + a4*t4
A2 | a1*t1 + a2*t2 + a3*t3 + a4*t4
The problem is, if I want to place some constraints on the thresholds, for instance to force a2 = -a3 and (a2-a1) = (a4-a3) like in this picture:
![Untitled.png](https://groups.google.com/group/lavaan/attach/1c685a78e7567/Untitled.png?part=0.1&view=1)
then how we will modify the code to obtain this?
Thank you so much for reading this topic.
Best,
Tran Viet Yen.