Mplus Users Guide v6.. - Muthén & Muthén

Examples: Multilevel Modeling With Complex Survey DataThe CATEGORICAL option is used to specify which dependentvariables are treated as binary or ordered categorical (ordinal) variablesin the model and its estimation. In the example above, u1, u2, u3, and u4are binary or ordered categorical variables. They represent the outcomemeasured at four equidistant occasions.The default estimator for this type of analysis is maximum likelihoodwith robust standard errors using a numerical integration algorithm.Note that numerical integration becomes increasingly morecomputationally demanding as the number of factors and the sample sizeincrease. In this example, four dimensions of integration are used with atotal of 2,401 integration points. The INTEGRATION option of theANALYSIS command is used to change the number of integration pointsper dimension from the default of 15 to 7. The ESTIMATOR option ofthe ANALYSIS command can be used to select a different estimator.For models with many dimensions of integration and categoricaloutcomes, the weighted least squares estimator may improvecomputational speed.In the parameterization of the growth model shown here, the thresholdsof the outcome variable at the four time points are held equal as thedefault and are estimated in the between part of the model. Theintercept of the intercept growth factor is fixed at zero. The intercept ofthe slope growth factor is estimated as the default in the between part ofthe model. The residual variances of the growth factors are estimated asthe default. The residuals of the growth factors are correlated as thedefault because residuals are correlated for latent variables that do notinfluence any other variable in the model except their own indicators.On the between level, the residual variances of the random intercepts u1,u2, u3, and u4 are fixed at zero as the default.The OUTPUT command is used to request additional output notincluded as the default. The TECH1 option is used to request the arrayscontaining parameter specifications and starting values for all freeparameters in the model. The TECH8 option is used to request that theoptimization history in estimating the model be printed in the output.TECH8 is printed to the screen during the computations as the default.TECH8 screen printing is useful for determining how long the analysistakes. An explanation of the other commands can be found in Examples9.1 and 9.12.273