Mplus Users Guide v6.. - Muthén & Muthén

CHAPTER 7In the MODEL command, user-specified starting values are given for thethresholds of the binary latent class indicators. For binary and orderedcategorical dependent variables, thresholds are referred to by adding to avariable name a dollar sign ($) followed by a threshold number. Thenumber of thresholds is equal to the number of categories minus one.Because the latent class indicators are binary, they have one threshold.The thresholds of the latent class indicators are referred to as u1$1,u2$1, u3$1, and u4$1. Square brackets are used to specify startingvalues in the logit scale for the thresholds of the binary latent classindicators. The asterisk (*) is used to assign a starting value. It is placedafter a variable with the starting value following it. In the exampleabove, the threshold of u1 is assigned the starting value of 1 for class 1and -1 for class 2. The threshold of u4 is assigned the starting value of -1 for class 1 and 1 for class 2. The default estimator for this type ofanalysis is maximum likelihood with robust standard errors. TheESTIMATOR option of the ANALYSIS command can be used to selecta different estimator. An explanation of the other commands can befound in Examples 7.1 and 7.3.EXAMPLE 7.5: LCA WITH BINARY LATENT CLASSINDICATORS USING USER-SPECIFIED STARTING VALUESWITH RANDOM STARTSTITLE: this is an example of a LCA with binarylatent class indicators using userspecifiedstarting values with randomstartsDATA: FILE IS ex7.5.dat;VARIABLE: NAMES ARE u1-u4;CLASSES = c (2);CATEGORICAL = u1-u4;ANALYSIS: TYPE = MIXTURE;STARTS = 100 10;STITERATIONS = 20;MODEL:%OVERALL%%c#1%[u1$1*1 u2$1*1 u3$1*-1 u4$1*-1];%c#2%[u1$1*-1 u2$1*-1 u3$1*1 u4$1*1];OUTPUT: TECH1 TECH8;154