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Michael Li posted on Thursday, October 01, 2015 - 8:59 pm
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Dear Dr. Muthen, I've read recommendations for conducting GMM, and most involves the following steps: identify the number of trajectories, examine covariates associated with the trajectories, and then test a final GMM that included relevant covariates. However, I'm not quite understand that after I examine covariates significantly associated with the trajectories, why should I included relevant covariates in the final model? What's the differences between conditional and the unconditional GMM? Thank you for your help! Regards, Michael |
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You don't have to take that final step. But it can be useful for example to check if there are direct influences from covariates to growth factors or outcomes - which would make decisions on the number of classes different from using the unconditinal GMM. See also the paper on our website: Petras, H. & Masyn, K. "General growth mixture analysis with antecedents and consequences of change." Handbook of Quantitative Criminology. Ed. Alex Piquero, Ed. David Weisburd. New York: Springer-Verlag, 2010. 69-100. download paper contact first author |
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