On Asymptotic Optimality of Least Squares Model Averaging When True Model Is Included

Fuente: arXiv
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Autori principali: Xu, Wenchao, Zhang, Xinyu
Natura: Preprint
Pubblicazione: 2024
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author Xu, Wenchao
Zhang, Xinyu
author_facet Xu, Wenchao
Zhang, Xinyu
contents Asymptotic optimality is a key theoretical property in model averaging. Due to technical difficulties, existing studies rely on restricted weight sets or the assumption that there is no true model with fixed dimensions in the candidate set. The focus of this paper is to overcome these difficulties. Surprisingly, we discover that when the penalty factor in the weight selection criterion diverges with a certain order and the true model dimension is fixed, asymptotic loss optimality does not hold, but asymptotic risk optimality does. This result differs from the corresponding result of Fang et al. (2023, Econometric Theory 39, 412-441) and reveals that using the discrete weight set of Hansen (2007, Econometrica 75, 1175-1189) can yield opposite asymptotic properties compared to using the usual weight set. Simulation studies illustrate the theoretical findings in a variety of settings.
format Preprint
id arxiv_https___arxiv_org_abs_2411_09258
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On Asymptotic Optimality of Least Squares Model Averaging When True Model Is Included
Xu, Wenchao
Zhang, Xinyu
Statistics Theory
Econometrics
Asymptotic optimality is a key theoretical property in model averaging. Due to technical difficulties, existing studies rely on restricted weight sets or the assumption that there is no true model with fixed dimensions in the candidate set. The focus of this paper is to overcome these difficulties. Surprisingly, we discover that when the penalty factor in the weight selection criterion diverges with a certain order and the true model dimension is fixed, asymptotic loss optimality does not hold, but asymptotic risk optimality does. This result differs from the corresponding result of Fang et al. (2023, Econometric Theory 39, 412-441) and reveals that using the discrete weight set of Hansen (2007, Econometrica 75, 1175-1189) can yield opposite asymptotic properties compared to using the usual weight set. Simulation studies illustrate the theoretical findings in a variety of settings.
title On Asymptotic Optimality of Least Squares Model Averaging When True Model Is Included
topic Statistics Theory
Econometrics
url https://arxiv.org/abs/2411.09258