Modelling count data using the logratio-normal-multinomial distribution

The logratio-normal-multinomial distribution is a count data model resulting from compounding a multinomial distribution for the counts with a multivariate logratio-normal distribution for the multinomial event probabilities. However, the logratio-normal-multinomial probability mass function does no...

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Detalles Bibliográficos
Autores: Comas-Cufí, Marc|||0000-0001-9759-0622, Martín-Fernández, Josep-Antoni|||0000-0003-2366-1592, Mateu-Figueras, Glòria|||0000-0002-2477-2764, Palarea-Albaladejo, Javier|||0000-0003-0162-669X
Tipo de recurso: artículo
Fecha de publicación:2020
País:España
Institución:Universitat Autònoma de Barcelona
Repositorio:Dipòsit Digital de Documents de la UAB
Idioma:inglés
OAI Identifier:oai:ddd.uab.cat:225688
Acceso en línea:https://ddd.uab.cat/record/225688
https://dx.doi.org/urn:doi:10.2436/20.8080.02.96
Access Level:acceso abierto
Palabra clave:Count data
Compound probability distribution
Dirichlet multinomial
Logratio coordinates
Monte carlo method
Simplex
Descripción
Sumario:The logratio-normal-multinomial distribution is a count data model resulting from compounding a multinomial distribution for the counts with a multivariate logratio-normal distribution for the multinomial event probabilities. However, the logratio-normal-multinomial probability mass function does not admit a closed form expression and, consequently, numerical approximation is required for parameter estimation. In this work, different estimation approaches are introduced and evaluated. We concluded that estimation based on a quasi-Monte Carlo Expectation-Maximisation algorithm provides the best overall results. Building on this, the performances of the Dirichlet-multinomial and logratio-normal-multinomial models are compared through a number of examples using simulated and real count data.