I would like to use the new two-step procedure suggested by Bakk & Kuha (2018, Psychometrika) for an LTA. For this purpose I have estimated two separate LCA’s (input and output files attached).
However, when I feed the starting values from these (using the output from “svalues”) into a LTA, the classes change. To clarify: in this second step I am only interested in the structural parameter linking the two LCA’s (c1 and c2).
I wonder if perhaps you could you provide some help with the correct syntax for the second step?
The example in the article primarily deals with LCA. However, they note (on p. 877) that the method easily extends to more complicated cases.
They write: "For instance, suppose that there are two latent class variables X1 and X2 with separate sets of indicators Y1 and Y2, and the structural model is of the form p(X1)p(Z1|X1)p(X2|Z1, X1)p(Z2|X1, Z1, X2). In step 1, we would then estimate two separate latent class models, one for X1 and one for X2 (and both again without Z = (Z1, Z2)). Step 1 parameters θ1 would be the measurement probabilities of X1 and X2 and the parameters of p(X1), and step 2 parameters would be those of the rest of the structural model apart from p(X1)."
In most situations, I would expect the DAT method, the two-step method, the three-step method and the BCH method to yield similar results. If you have an example where that is not the case send it to firstname.lastname@example.org