refined-weissman
Résumé
Weissman extrapolation methodology for estimating extreme quantiles from heavy-tailed
distributions is based on two estimators: an order statistic to estimate an intermediate quantile
and an estimator of the tail-index. The common practice is to select the same intermediate
sequence for both estimators. In this work, we show how an adapted choice of two different
intermediate sequences leads to a reduction of the asymptotic bias associated with the resulting
refined Weissman estimator. The asymptotic normality of the latter estimator is established
and a data-driven method is introduced for the practical selection of the intermediate sequences.
Our approach is compared to Weissman estimator and to six bias reduced estimators of extreme
quantiles on a large scale simulation study. It appears that the refined Weissman estimator
outperforms its competitors in a wide variety of situations, especially in the challenging high
bias cases. Finally, an illustration on an actuarial real data set is provided.