Math @ Duke

Publications [#257973] of David B. Dunson
search www.stat.duke.edu.Papers Published
 Bhattacharya, A; Dunson, DB, Simplex Factor Models for Multivariate Unordered Categorical Data.,
Journal of the American Statistical Association, vol. 107 no. 497
(March, 2012),
pp. 362377, ISSN 01621459 [doi]
(last updated on 2018/08/17)
Abstract: Gaussian latent factor models are routinely used for modeling of dependence in continuous, binary, and ordered categorical data. For unordered categorical variables, Gaussian latent factor models lead to challenging computation and complex modeling structures. As an alternative, we propose a novel class of simplex factor models. In the singlefactor case, the model treats the different categorical outcomes as independent with unknown marginals. The model can characterize flexible dependence structures parsimoniously with few factors, and as factors are added, any multivariate categorical data distribution can be accurately approximated. Using a Bayesian approach for computation and inferences, a Markov chain Monte Carlo (MCMC) algorithm is proposed that scales well with increasing dimension, with the number of factors treated as unknown. We develop an efficient proposal for updating the base probability vector in hierarchical Dirichlet models. Theoretical properties are described, and we evaluate the approach through simulation examples. Applications are described for modeling dependence in nucleotide sequences and prediction from highdimensional categorical features.


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