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Modelling covariance structure in bivariate marginal models for longitudinal data

Xu, Jing (2012) Modelling covariance structure in bivariate marginal models for longitudinal data. Biometrika 2012 (3), pp. 649-662. ISSN 1464-3510.

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Abstract

It can be more challenging to efficiently model the covariance matrices for multivariate longitudinal data than for the univariate case, due to the correlations arising between multiple responses. The positive-definiteness constraint and the high dimensionality are further obstacles in covariance modelling. In this paper, we develop a data-based method by which the parameters in the covariancematrices are replaced by unconstrained and interpretable parameterswith reduced dimensions. The maximum likelihood estimators for the mean and covariance parameters are shown to be consistent and asymptotically normally distributed. Simulations and real data analysis show that the new approach performs very well even when modelling bivariate nonstationary dependence structures.

Metadata

Item Type: Article
Keyword(s) / Subject(s): bivariate marginal model, block triangular factorization, covariance modelling, log-innovation matrix modelling, longitudinal data, matrix logarithm
School: Birkbeck Faculties and Schools > Faculty of Business and Law > Birkbeck Business School
Depositing User: Jing Xu
Date Deposited: 25 Jan 2013 10:04
Last Modified: 01 Aug 2025 18:07
URI: https://eprints.bbk.ac.uk/id/eprint/5439

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