Mplus Users Guide v6.. - Muthén & Muthén

CHAPTER 17LABELING CLASSES OF A CATEGORICALLATENT VARIABLEIn the MODEL command, categorical latent variable classes are referredto using labels. These labels are constructed by using the convention ofadding to the name of the categorical latent variable a number signfollowed by a number. For example, if c is a categorical latent variablewith four classes, the labels for the four classes are c#1, c#2, and c#3.The last class is the reference class.LABELING PARAMETERSLabels can be assigned to parameters by placing a name in parenthesesfollowing the parameter in the MODEL command. These labels areused in conjunction with the MODEL CONSTRAINT command todefine linear and non-linear constraints on the parameters in the model.Labels can be assigned to parameters not in the MODEL command usingthe NEW option of the MODEL CONSTRAINT command. Both typesof labels can be used with the MODEL TEST command to test linearrestrictions on the model defined in the MODEL and MODELCONSTRAINT commands.The parameter labels follow the same rules as variable names. They canbe up to 8 characters in length; must begin with a letter; can contain onlyletters, numbers, and the underscore symbol; and are not case sensitive.Following is an example of how to label parameters:MODEL:y ON x1 (p1)x2 (p2)x3 (p3);where p1 is the label assigned to the regression slope for y on x1, p2 isthe label assigned to the regression slope for y on the x2, and p3 is thelabel assigned to the regression slope for y on x3. Note that only onelabel can appear on a line.SCALE FACTORSIn models that use TYPE=GENERAL, it may be useful to multiply eachobserved variable or latent response variable by a scale factor that can be600