Weak Identification with Many Instruments

Fuente: arXiv
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Main Authors: Mikusheva, Anna, Sun, Liyang
Format: Preprint
Published: 2023
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author Mikusheva, Anna
Sun, Liyang
author_facet Mikusheva, Anna
Sun, Liyang
contents Linear instrumental variable regressions are widely used to estimate causal effects. Many instruments arise from the use of ``technical'' instruments and more recently from the empirical strategy of ``judge design''. This paper surveys and summarizes ideas from recent literature on estimation and statistical inferences with many instruments for a single endogenous regressor. We discuss how to assess the strength of the instruments and how to conduct weak identification-robust inference under heteroskedasticity. We establish new results for a jack-knifed version of the Lagrange Multiplier (LM) test statistic. Furthermore, we extend the weak-identification-robust tests to settings with both many exogenous regressors and many instruments. We propose a test that properly partials out many exogenous regressors while preserving the re-centering property of the jack-knife. The proposed tests have correct size and good power properties.
format Preprint
id arxiv_https___arxiv_org_abs_2308_09535
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Weak Identification with Many Instruments
Mikusheva, Anna
Sun, Liyang
Econometrics
Linear instrumental variable regressions are widely used to estimate causal effects. Many instruments arise from the use of ``technical'' instruments and more recently from the empirical strategy of ``judge design''. This paper surveys and summarizes ideas from recent literature on estimation and statistical inferences with many instruments for a single endogenous regressor. We discuss how to assess the strength of the instruments and how to conduct weak identification-robust inference under heteroskedasticity. We establish new results for a jack-knifed version of the Lagrange Multiplier (LM) test statistic. Furthermore, we extend the weak-identification-robust tests to settings with both many exogenous regressors and many instruments. We propose a test that properly partials out many exogenous regressors while preserving the re-centering property of the jack-knife. The proposed tests have correct size and good power properties.
title Weak Identification with Many Instruments
topic Econometrics
url https://arxiv.org/abs/2308.09535