Mplus Users Guide v6.. - Muthén & Muthén

Special Modeling IssuesThe following group-specific MODEL command relaxes the equalityconstraints on the intercepts of the observed dependent variables:MODEL g2:[y1-y10];SCALE FACTORS IN MULTIPLE GROUPANALYSISScale factors can be used in multiple group analysis. They arerecommended when observed dependent variables are categorical and aweighted least squares estimator is used. They capture across groupdifferences in the variances of the latent response variables for theobserved categorical dependent variables. Scale factors are part of themodel as the default using a weighted least squares estimator when oneor more observed dependent variables are categorical. In this situation,the first group has scale factors fixed at one. In the other groups, scalefactors are free to be estimated with starting values of one. Scale factorsare referred to using curly brackets. Following is an example of how torefer to scale factors in a model with multiple groups where u1, u2, u3,u4, and u5 are observed categorical dependent variables.MODEL:MODEL g2:f BY u1-u5;{u1-u5*.5};In the above example, the scale factors of the latent response variables ofthe observed categorical dependent variables in g1 are fixed at one as thedefault. Starting values are given for the free scale factors in g2.RESIDUAL VARIANCES OF LATENT RESPONSEVARIABLES IN MULTIPLE GROUP ANALYSISWith the Theta parameterization for observed categorical dependentvariables using a weighted least squares estimator, residual variances ofthe latent response variables for the observed categorical dependentvariables are part of the model as the default. In this situation, the firstgroup has residual variances fixed at one for all observed categoricaldependent variables. In the other groups, residual variances are free tobe estimated with starting values of one. Residual variances of the latentresponse variables are referred to using the name of the correspondingobserved variable. Following is an example of how to refer to residual429