Mplus Users Guide v6.. - Muthén & Muthén

CHAPTER 9timesya3Withinx1yBetweenx2sIn this example, a linear growth model for a continuous outcome withtime-invariant and time-varying covariates as shown in the picture aboveis estimated. As part of the analysis, the DATA WIDETOLONGcommand is used to rearrange the data from a multivariate wide formatto a univariate long format. The model is similar to the one in Example6.10 using multivariate wide format data. The differences are that thecurrent model restricts the within-level residual variances to be equalacross time and the within-level influence of the time-varying covariateon the outcome to be equal across time.The WIDE option of the DATA WIDETOLONG command is used toidentify sets of variables in the wide format data set that are to beconverted into single variables in the long format data set. Thesevariables must variables from the NAMES statement of the VARIABLEcommand. The two sets of variables y11, y12, y13, and y14 and a31,a32, a33, and a34 are identified. The LONG option is used to providenames for the new variables in the long format data set. The names yand a3 are the names of the new variables. The IDVARIABLE option isused to provide a name for the variable that provides information aboutthe unit to which the record belongs. In univariate growth modeling, thisis the person identifier which is used as a cluster variable. In thisexample, the name person is used. This option is not required. The282