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LCA General Description

2. LCA General Description. People (or objects) from a heterogeneous population assumed to belong to a limited number of homogeneous groups referred to as latent classes"Latent classes are categories of a latent variable, each one of which contains individuals who are similar to each other and di

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LCA General Description

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    1. 1 LCA General Description Statistical method for finding subtypes of related cases from multivariate categorical data LCA concerned with the structure of cases (i.e., the latent taxonomic structure) person-centered differs from factor analysis which is concerned with the structure of variables similar to cluster analysis, but is based on probabilistic theory

    2. 2 LCA General Description People (or objects) from a heterogeneous population assumed to belong to a limited number of homogeneous groups referred to as “latent classes” Latent classes are categories of a latent variable, each one of which contains individuals who are similar to each other and different from individuals in other categories

    3. 3 Good examples of LCA Patterns of cigarette smoking(Chen et al., 2004) General substance use(Flaherty, 2002) Grouping cancer patients by psychosocial needs(Soothill, 2004) Types of infant temperament(Loken, 2004) Attention-deficit/hyperactivity typology(Neuman et al., 1999) Eating disorder phenotypes(Keel et al., 2004) Subtypes of depression(Parker et al., 1999) Structure of psychosis (Kendler et al., 1998) Metabolic control(Seiffge-Krenke & Stemmler, 2003)

    4. 4 What would the data look like?

    5. 5 kp ? 23 = 8 Possible Response Patterns

    6. 6 Purpose of LCA Use patterns of responses to observed categorical variables to: identify the number of underlying classes classify each individual into one class and determine class size

    7. 7 How LCA Works There are 2 primary model parameters the prevalence of each case in a class (latent class probabilities; LCP) e.g., the proportion of individuals in "disease present" vs. "disease absent" latent classes conditional response probability (CRP) the probability that an individual within a particular class will respond "present" or "yes" to a target item e.g., the probability for each symptom (item) within a latent class being present

    8. 8 The LCA Model Observed Categorical Items (u’s) Categorical Latent Class Variable (c) Continuous or Categorical Covariates (x)

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