Mplus Users Guide v6.. - Muthén & Muthén

CHAPTER 18of draws varies from 2 to 100. This method gives an approximation tothe p-value. A more precise estimate of the p-value is obtained by usinga full set of bootstrap draws using the LRTBOOTSTRAP option of theANALYSIS command. A common value suggested in the literature is100 bootstrap draws (McLachlan & Peel, 2000). For more informationabout TECH14, see Nylund et al. (2007).In the TECH14 output, the H0 loglikelihood value given is for the k-1class model. It is important to check that the H0 loglikelihood value inthe TECH14 output is the same as the loglikelihood value for the H0model obtained in a previous k-1 class analysis. If it is not the same, theK-1STARTS option of the ANALYSIS command can be used toincrease the number of random starts for the estimation of the k-1 classmodel for TECH14.TECH14 computations are time consuming because for each bootstrapdraw random starts are needed for the k class model. The default for thek class model is to generate 20 random sets of starting values in theinitial stage followed by 5 optimizations in the final stage. The defaultvalues can be changed using the LRTSTARTS option of the ANALYSIScommand. The following steps are recommended to save computationaltime when using TECH14:1. Run without TECH14 using the STARTS option of the ANALYSIScommand to find a stable solution if the default starts are notsufficient.2. Run with TECH14 using the OPTSEED option of the ANALYSIScommand to specify the seed of the stable solution from Step 1.3. Run with LRTSTARTS = 0 0 40 10; to check if the results aresensitive to the number of random starts for the k class model.Mplus PARAMETER ARRAYSFollowing is a description of some parameter arrays that are commonlyused in model estimation. The first nine arrays are for the structuralequation part of the model. The remaining eight arrays are for themixture part of the model.660