Bayesian copula selection

  • Authors:
  • David Huard;Guillaume ívin;Anne-Catherine Favre

  • Affiliations:
  • Institut National de la Recherche Scientifique, Centre Eau, Terre & Environnement, Quéé., Canada G1K 9A9;Institut National de la Recherche Scientifique, Centre Eau, Terre & Environnement, Quéé., Canada G1K 9A9;Institut National de la Recherche Scientifique, Centre Eau, Terre & Environnement, Quéé., Canada G1K 9A9

  • Venue:
  • Computational Statistics & Data Analysis
  • Year:
  • 2006

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Abstract

In recent years, the use of copulas has grown extremely fast and with it, the need for a simple and reliable method to choose the right copula family. Existing methods pose numerous difficulties and none is entirely satisfactory. We propose a Bayesian method to select the most probable copula family among a given set. The copula parameters are treated as nuisance variables, and hence do not have to be estimated. Furthermore, by a parameterization of the copula density in terms of Kendall's @t, the prior on the parameter is replaced by a prior on @t, conceptually more meaningful. The prior on @t, common to all families in the set of tested copulas, serves as a basis for their comparison. Using simulated data sets, we study the reliability of the method and observe the following: (1) the frequency of successful identification approaches 100% as the sample size increases, (2) for weakly correlated variables, larger samples are necessary for reliable identification.