Resistant Inference in Instrumental Variable Models

Fuente: arXiv
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Autori principali: Klooster, Jens, Zhelonkin, Mikhail
Natura: Preprint
Pubblicazione: 2024
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author Klooster, Jens
Zhelonkin, Mikhail
author_facet Klooster, Jens
Zhelonkin, Mikhail
contents The classical tests in the instrumental variable model can behave arbitrarily if the data is contaminated. For instance, one outlying observation can be enough to change the outcome of a test. We develop a framework to construct testing procedures that are robust to weak instruments, outliers and heavy-tailed errors in the instrumental variable model. The framework is constructed upon M-estimators. By deriving the influence functions of the classical weak instrument robust tests, such as the Anderson-Rubin test, K-test and the conditional likelihood ratio (CLR) test, we prove their unbounded sensitivity to infinitesimal contamination. Therefore, we construct contamination resistant/robust alternatives. In particular, we show how to construct a robust CLR statistic based on Mallows type M-estimators and show that its asymptotic distribution is the same as that of the (classical) CLR statistic. The theoretical results are corroborated by a simulation study. Finally, we revisit three empirical studies affected by outliers and demonstrate how the new robust tests can be used in practice.
format Preprint
id arxiv_https___arxiv_org_abs_2403_16844
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Resistant Inference in Instrumental Variable Models
Klooster, Jens
Zhelonkin, Mikhail
Econometrics
Methodology
The classical tests in the instrumental variable model can behave arbitrarily if the data is contaminated. For instance, one outlying observation can be enough to change the outcome of a test. We develop a framework to construct testing procedures that are robust to weak instruments, outliers and heavy-tailed errors in the instrumental variable model. The framework is constructed upon M-estimators. By deriving the influence functions of the classical weak instrument robust tests, such as the Anderson-Rubin test, K-test and the conditional likelihood ratio (CLR) test, we prove their unbounded sensitivity to infinitesimal contamination. Therefore, we construct contamination resistant/robust alternatives. In particular, we show how to construct a robust CLR statistic based on Mallows type M-estimators and show that its asymptotic distribution is the same as that of the (classical) CLR statistic. The theoretical results are corroborated by a simulation study. Finally, we revisit three empirical studies affected by outliers and demonstrate how the new robust tests can be used in practice.
title Resistant Inference in Instrumental Variable Models
topic Econometrics
Methodology
url https://arxiv.org/abs/2403.16844