I've used OpenMX to duplicate an MX model using bivariate Cholesky of alcohol use disorder symptoms (ordinal variable with 4 thresholds) and remission (bivariate). Results are similar but I cannot figure out how to test a submodel that equates male and female parameters on the threshold variables (first has 4 thresholds, second has just one). Any ideas? From what I've read OpenMX may still be a little dicey with ordinal variables? Script attached.