Mplus Users Guide v6.. - Muthén & Muthén

CHAPTER 12MODEL:OUTPUT:iu su | u1@0 u2@1 u3@2 u4@3;[u1$1-u4$1*-.5] (1);[iu@0 su*.85];iu*1.45;su@0;iy sy | y1@0 y2@1 y3@2 y4@3;[y1-y4@0];y1-y4*.5;[iy*.5 sy*1];iy*1;sy*.2;iy WITH sy*.1;iu WITH iy*0.9;iu WITH sy@0;TECH8;In this example, data are generated and analyzed for a two-part(semicontinuous) growth model for a continuous outcome like the oneshown in Example 6.16. If these data are saved for subsequent two-partanalysis using the DATA TWOPART command, an adjustment to thesaved data must be made using the DEFINE command as part of theanalysis. If the values of the continuous outcomes y are not 999 which isthe value used as the missing data flag in the saved data, the exponentialfunction must be applied to the continuous variables. After thattransformation, the value 999 must be changed to zero for the continuousvariables. This represents the floor of the scale.The MISSING option in the MONTECARLO command is used toidentify the dependent variables in the data generation model for whichmissing data will be generated. The MODEL MISSING command isused to provide information about the population parameter values forthe missing data model to be used in the generation of data. TheMODEL MISSING command specifies a logistic regression model for aset of binary dependent variables that represent not missing (scored as 0)and missing (scored as 1) for the dependent variables in the datageneration model. The binary missing data indicators have the samenames as the dependent variables in the data generation model. The firststatement in the MODEL MISSING command defines the intercepts inthe logistic regressions for the binary dependent variables y1, y2, y3, andy4. If the covariates predicting missingness all have values of zero, thelogistic regression intercept value of 15 corresponds to a probability ofone of having missing data on the dependent variables. The four ONstatements describe the regressions of the missing value indicators y1,y2, y3, and y4 on the binary outcomes u1, u2, u3, and u4 where the384