Bayesian nonparametric models for zero-inflated count-compositional data using ensembles of regression trees

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Autori principali: Menezes, André F. B., Parnell, Andrew C., Murphy, Keefe
Natura: Preprint
Pubblicazione: 2026
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author Menezes, André F. B.
Parnell, Andrew C.
Murphy, Keefe
author_facet Menezes, André F. B.
Parnell, Andrew C.
Murphy, Keefe
contents Count-compositional data arise in many different fields, including high-throughput sequencing experiments, ecological surveys, and palaeoclimate studies, where a common, important goal is to understand how covariates relate to the observed compositions. Existing methods often fail to simultaneously address key challenges inherent in such data, namely: overdispersion, an excess of zeros, cross-sample heterogeneity, and complex covariate effects. To address these concerns, we propose two novel Bayesian models based on ensembles of regression trees. Specifically, we leverage the recently introduced zero-and-$N$-inflated multinomial distribution and assign independent nonparametric Bayesian additive regression tree (BART) priors to both the compositional and structural zero probability components of the model, to flexibly capture covariate effects. We further extend this by adding latent random effects to capture overdispersion and more general dependence structures among the categories. We develop an efficient inferential algorithm combining recent data augmentation schemes with established BART sampling routines. We evaluate our proposed models in simulation studies and illustrate their applicability through a case study of palaeoclimate modelling.
format Preprint
id arxiv_https___arxiv_org_abs_2601_08067
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Bayesian nonparametric models for zero-inflated count-compositional data using ensembles of regression trees
Menezes, André F. B.
Parnell, Andrew C.
Murphy, Keefe
Methodology
62F15, 62G08 (primary), 62P10 (secondary)
Count-compositional data arise in many different fields, including high-throughput sequencing experiments, ecological surveys, and palaeoclimate studies, where a common, important goal is to understand how covariates relate to the observed compositions. Existing methods often fail to simultaneously address key challenges inherent in such data, namely: overdispersion, an excess of zeros, cross-sample heterogeneity, and complex covariate effects. To address these concerns, we propose two novel Bayesian models based on ensembles of regression trees. Specifically, we leverage the recently introduced zero-and-$N$-inflated multinomial distribution and assign independent nonparametric Bayesian additive regression tree (BART) priors to both the compositional and structural zero probability components of the model, to flexibly capture covariate effects. We further extend this by adding latent random effects to capture overdispersion and more general dependence structures among the categories. We develop an efficient inferential algorithm combining recent data augmentation schemes with established BART sampling routines. We evaluate our proposed models in simulation studies and illustrate their applicability through a case study of palaeoclimate modelling.
title Bayesian nonparametric models for zero-inflated count-compositional data using ensembles of regression trees
topic Methodology
62F15, 62G08 (primary), 62P10 (secondary)
url https://arxiv.org/abs/2601.08067