Semiparametric inference using fractional posteriors

Fuente: arXiv
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Main Authors: L'Huillier, Alice, Travis, Luke, Castillo, Ismaël, Ray, Kolyan
Format: Preprint
Published: 2023
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author L'Huillier, Alice
Travis, Luke
Castillo, Ismaël
Ray, Kolyan
author_facet L'Huillier, Alice
Travis, Luke
Castillo, Ismaël
Ray, Kolyan
contents We establish a general Bernstein--von Mises theorem for approximately linear semiparametric functionals of fractional posterior distributions based on nonparametric priors. This is illustrated in a number of nonparametric settings and for different classes of prior distributions, including Gaussian process priors. We show that fractional posterior credible sets can provide reliable semiparametric uncertainty quantification, but have inflated size. To remedy this, we further propose a \textit{shifted-and-rescaled} fractional posterior set that is an efficient confidence set having optimal size under regularity conditions. As part of our proofs, we also refine existing contraction rate results for fractional posteriors by sharpening the dependence of the rate on the fractional exponent.
format Preprint
id arxiv_https___arxiv_org_abs_2301_08158
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Semiparametric inference using fractional posteriors
L'Huillier, Alice
Travis, Luke
Castillo, Ismaël
Ray, Kolyan
Statistics Theory
Machine Learning
62G
We establish a general Bernstein--von Mises theorem for approximately linear semiparametric functionals of fractional posterior distributions based on nonparametric priors. This is illustrated in a number of nonparametric settings and for different classes of prior distributions, including Gaussian process priors. We show that fractional posterior credible sets can provide reliable semiparametric uncertainty quantification, but have inflated size. To remedy this, we further propose a \textit{shifted-and-rescaled} fractional posterior set that is an efficient confidence set having optimal size under regularity conditions. As part of our proofs, we also refine existing contraction rate results for fractional posteriors by sharpening the dependence of the rate on the fractional exponent.
title Semiparametric inference using fractional posteriors
topic Statistics Theory
Machine Learning
62G
url https://arxiv.org/abs/2301.08158