Robust and Computationally Efficient Trimmed L-Moments Estimation for Parametric Distributions

Fuente: arXiv
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Auteurs principaux: Poudyal, Chudamani, Zhao, Qian, Sitaula, Hari
Format: Preprint
Publié: 2025
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author Poudyal, Chudamani
Zhao, Qian
Sitaula, Hari
author_facet Poudyal, Chudamani
Zhao, Qian
Sitaula, Hari
contents This paper proposes a robust and computationally efficient estimation framework for fitting parametric distributions based on trimmed L-moments. Trimmed L-moments extend classical L-moment theory by downweighting or excluding extreme order statistics, resulting in estimators that are less sensitive to outliers and heavy tails. We construct estimators for both location-scale and shape parameters using asymmetric trimming schemes tailored to different moments, and establish their asymptotic properties for inferential justification using the general structural theory of L-statistics, deriving simplified single-integration expressions to ensure numerical stability. State-of-the-art algorithms are developed to resolve the sign ambiguity in estimating the scale parameter for location-scale models and the tail index for the Frechet model. The proposed estimators offer improved efficiency over traditional robust alternatives for selected asymmetric trimming configurations, while retaining closed-form expressions for a wide range of common distributions, facilitating fast and stable computation. Simulation studies demonstrate strong finite-sample performance. An application to financial claim severity modeling highlights the practical relevance and flexibility of the approach.
format Preprint
id arxiv_https___arxiv_org_abs_2505_09860
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Robust and Computationally Efficient Trimmed L-Moments Estimation for Parametric Distributions
Poudyal, Chudamani
Zhao, Qian
Sitaula, Hari
Methodology
Statistics Theory
Applications
Computation
This paper proposes a robust and computationally efficient estimation framework for fitting parametric distributions based on trimmed L-moments. Trimmed L-moments extend classical L-moment theory by downweighting or excluding extreme order statistics, resulting in estimators that are less sensitive to outliers and heavy tails. We construct estimators for both location-scale and shape parameters using asymmetric trimming schemes tailored to different moments, and establish their asymptotic properties for inferential justification using the general structural theory of L-statistics, deriving simplified single-integration expressions to ensure numerical stability. State-of-the-art algorithms are developed to resolve the sign ambiguity in estimating the scale parameter for location-scale models and the tail index for the Frechet model. The proposed estimators offer improved efficiency over traditional robust alternatives for selected asymmetric trimming configurations, while retaining closed-form expressions for a wide range of common distributions, facilitating fast and stable computation. Simulation studies demonstrate strong finite-sample performance. An application to financial claim severity modeling highlights the practical relevance and flexibility of the approach.
title Robust and Computationally Efficient Trimmed L-Moments Estimation for Parametric Distributions
topic Methodology
Statistics Theory
Applications
Computation
url https://arxiv.org/abs/2505.09860