Identification-Robust Testing in Endogenous Functional Linear Regression with Weak or Irrelevant Auxiliary Variables

Fuente: arXiv
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Main Author: Seo, Won-Ki
Format: Preprint
Published: 2026
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author Seo, Won-Ki
author_facet Seo, Won-Ki
contents We develop dimension-reduction-free tests for the slope function in functional linear regression when the functional regressor may be endogenous or measured with error. The tests are based on a functional moment condition induced by an auxiliary functional variable and do not require estimation of the slope function. This feature is particularly useful in infinite-dimensional settings, where the identification and regularization conditions needed for consistent estimation are often strong and difficult to verify. The proposed procedures remain asymptotically valid under weak or even failed relevance of the auxiliary variable, and they are consistent against fixed alternatives that are detectable through the moment operator. We establish the asymptotic null distribution, consistency against detectable alternatives, and local power under drifting alternatives. We also derive the locally optimal test within a class of weighted test statistics. Feasible critical values for implementation of the tests are obtained from data. Simulations show reliable size control and competitive power, including under weak relevance. We illustrate the method using a functional regression analysis of residential electricity demand and temperature distributions in South Korea.
format Preprint
id arxiv_https___arxiv_org_abs_2605_29972
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Identification-Robust Testing in Endogenous Functional Linear Regression with Weak or Irrelevant Auxiliary Variables
Seo, Won-Ki
Methodology
Statistics Theory
62R10, 62M10, 62J05, 62F03
We develop dimension-reduction-free tests for the slope function in functional linear regression when the functional regressor may be endogenous or measured with error. The tests are based on a functional moment condition induced by an auxiliary functional variable and do not require estimation of the slope function. This feature is particularly useful in infinite-dimensional settings, where the identification and regularization conditions needed for consistent estimation are often strong and difficult to verify. The proposed procedures remain asymptotically valid under weak or even failed relevance of the auxiliary variable, and they are consistent against fixed alternatives that are detectable through the moment operator. We establish the asymptotic null distribution, consistency against detectable alternatives, and local power under drifting alternatives. We also derive the locally optimal test within a class of weighted test statistics. Feasible critical values for implementation of the tests are obtained from data. Simulations show reliable size control and competitive power, including under weak relevance. We illustrate the method using a functional regression analysis of residential electricity demand and temperature distributions in South Korea.
title Identification-Robust Testing in Endogenous Functional Linear Regression with Weak or Irrelevant Auxiliary Variables
topic Methodology
Statistics Theory
62R10, 62M10, 62J05, 62F03
url https://arxiv.org/abs/2605.29972