Mplus Users Guide v6.. - Muthén & Muthén

CHAPTER 6In this example, the model for two parallel processes shown in thepicture above is estimated. Regressions among the growth factors areincluded in the model.The | statements are used to name and define the intercept and slopegrowth factors for the two linear growth models. The names i1 and s1on the left-hand side of the first | statement are the names of the interceptand slope growth factors for the first linear growth model. The names i2and s2 on the left-hand side of the second | statement are the names ofthe intercept and slope growth factors for the second linear growthmodel. The values on the right-hand side of the two | statements are thetime scores for the two slope growth factors. For both growth models,the time scores of the slope growth factors are fixed at 0, 1, 2, and 3 todefine a linear growth model with equidistant time points. The zero timescore for the slope growth factor at time point one defines the interceptfactors as initial status factors. The coefficients of the intercept growthfactors are fixed at one as part of the growth model parameterization.The residual variances of the outcome variables are estimated andallowed to be different across time, and the residuals are not correlatedas the default.In the parameterization of the growth model shown here, the interceptsof the outcome variables at the four time points are fixed at zero as thedefault. The means and variances of the intercept growth factors areestimated as the default, and the intercept growth factor covariance isestimated as the default because the intercept growth factors areindependent (exogenous) variables. The intercepts and residualvariances of the slope growth factors are estimated as the default, andthe slope growth factors are correlated as the default because residualsare correlated for latent variables that do not influence any other variablein the model except their own indicators.The two ON statements describe the regressions of the slope growthfactor for each process on the intercept growth factor of the otherprocess. The default estimator for this type of analysis is maximumlikelihood. The ESTIMATOR option of the ANALYSIS command canbe used to select a different estimator. An explanation of the othercommands can be found in Example 6.1.120