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Calibration Method. Bob Fountain May 17, 2005. Problem. Judge the estimate of the parameter α for a 1-parameter Archimedean copula. The method will use the relationship between α and Kendall’s τ. Sample tau. A consistent estimator of Kendall’s τ for two series. is. Kendall variable.
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Calibration Method Bob Fountain May 17, 2005
Problem Judge the estimate of the parameter α for a 1-parameter Archimedean copula. The method will use the relationship between α and Kendall’s τ.
Sample tau A consistent estimator of Kendall’s τ for two series is
Kendall variable The Kendall random variable is defined as where F is the true (unknown) joint distribution function of the two random variables.
Kendall distribution The Kendall distribution is the cdf of the Kendall random variable. Genest and Rivest show that the Kendall distribution is related to the generator of an Archimedean copula by
Step 1 Construct an estimate of the Kendall distribution by substituting a previous estimate of α. Call this distribution
Step 2 Define Then the empirical Kendall distribution is
Step 3 Compare the Kendall distribution based on the estimated α with the empirical Kendall distribution. This can be done both graphically and using any numerical measure of closeness of two distribution functions.