Mplus Users Guide v6.. - Muthén & Muthén

CHAPTER 7The first hypothesis is specified by placing (1) following the thresholdparameters for u2 and u3 in class 1 and (2) following the thresholdparameters for u2 and u3 in class 2. This holds the thresholds for thetwo latent class indicators equal to each other but not equal acrossclasses. The second hypothesis is specified by fixing the threshold of u1in class 2 to the logit value of -15. The third hypothesis is specifiedusing the MODEL CONSTRAINT command. The MODELCONSTRAINT command is used to define linear and non-linearconstraints on the parameters in the model. Parameters are given labelsby placing a name in parentheses after the parameter in the MODELcommand. In the MODEL command, the threshold of u4 in class 1 isgiven the label p1 and the threshold of u4 in class 2 is given the label p2.In the MODEL CONSTRAINT command, the linear constraint isdefined. The threshold of u4 in class 1 is equal to the negative value ofthe threshold of u4 in class 2. The default estimator for this type ofanalysis is maximum likelihood with robust standard errors. TheESTIMATOR option of the ANALYSIS command can be used to selecta different estimator. An explanation of the other commands can befound in Example 7.1.EXAMPLE 7.14: CONFIRMATORY LCA WITH TWOCATEGORICAL LATENT VARIABLESTITLE: this is an example of a confirmatory LCAwith two categorical latent variablesDATA: FILE IS ex7.14.dat;VARIABLE: NAMES ARE u1-u4 y1-y4;CLASSES = cu (2) cy (3);CATEGORICAL = u1-u4;ANALYSIS: TYPE = MIXTURE;PARAMETERIZATION = LOGLINEAR;MODEL:%OVERALL%cu WITH cy;164