Bayesian analysis of extreme events with threshold estimation

The aim of this paper is to analyze extremal events using Generalized Pareto Distributions (GPD), considering explicitly the uncertainty about the threshold. Current practice empirically determines this quantity and proceeds by estimating the GPD parameters based on data beyond it, discarding all th...

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Detalles Bibliográficos
Autores: Lopes, Hedibert Freitas, Assunção, Cibele Noronha Behrens, Gamerman, Dani
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2004
País:Brasil
Institución:Fundação Getulio Vargas (FGV)
Repositorio:Repositório Institucional do FGV (FGV Repositório Digital)
Idioma:inglés
OAI Identifier:oai:repositorio.fgv.br:10438/12961
Acceso en línea:http://hdl.handle.net/10438/12961
Access Level:acceso abierto
Palabra clave:Bayesian
Extreme value theory
MCMC
Mixture model
Threshold estimation
Economia
Econometria
Descripción
Sumario:The aim of this paper is to analyze extremal events using Generalized Pareto Distributions (GPD), considering explicitly the uncertainty about the threshold. Current practice empirically determines this quantity and proceeds by estimating the GPD parameters based on data beyond it, discarding all the information available be10w the threshold. We introduce a mixture model that combines a parametric form for the center and a GPD for the tail of the distributions and uses all observations for inference about the unknown parameters from both distributions, the threshold inc1uded. Prior distribution for the parameters are indirectly obtained through experts quantiles elicitation. Posterior inference is available through Markov Chain Monte Carlo (MCMC) methods. Simulations are carried out in order to analyze the performance of our proposed mode1 under a wide range of scenarios. Those scenarios approximate realistic situations found in the literature. We also apply the proposed model to a real dataset, Nasdaq 100, an index of the financiai market that presents many extreme events. Important issues such as predictive analysis and model selection are considered along with possible modeling extensions.