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Title: The analysis of longitudinal mixed data via multivariate latent variable models: An analysis on alcohol use disorder Authors:  Silvia Cagnone - University of Bologna (Italy) [presenting]
Cinzia Viroli - University of Bologna (Italy)
Abstract: Alcohol abuse is a dangerous habit in young people. The National Youth Survey is a longitudinal American study in part devoted to the investigation of alcohol disorder over time. The symptoms of alcohol disorder are measured by binary and ordinal items. In the literature it is well recognized that alcohol abuse can be measured by a latent construct; therefore generalized latent variable models for mixed data represent the ideal framework to analyse these data. However, it might be desirable to cluster individuals according to the different severity of their alcohol use disorder and to investigate how the groups vary over time. We present a new methodological framework that includes two levels of latent variables: one continuous hidden variable for dimension reduction and clustering and a discrete random variable accounting for the dynamics of alcohol disorder symptoms. The effect of covariates is also measured and a testing procedure for the temporal assumption is developed. Three important issues are discussed. First, it represents a unified framework for the analysis of longitudinal multivariate mixed data. Secondly, it captures and models the unobserved heterogeneity of the data. Finally, it describes the dynamics of the data through the definition of latent constructs.