Bootstrap Tests for Overidentification in Linear Regression Models

We study the finite-sample properties of tests for overidentifying restrictions in linear regression models with a single endogenous regressor and weak instruments. Under the assumption of Gaussian disturbances, we derive expressions for a variety of test statistics as functions of eight mutually in...

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Bibliographic Details
Main Authors: Russell Davidson, James G. MacKinnon
Format: Article
Language:English
Published: MDPI AG 2015-12-01
Series:Econometrics
Subjects:
Online Access:http://www.mdpi.com/2225-1146/3/4/825
Description
Summary:We study the finite-sample properties of tests for overidentifying restrictions in linear regression models with a single endogenous regressor and weak instruments. Under the assumption of Gaussian disturbances, we derive expressions for a variety of test statistics as functions of eight mutually independent random variables and two nuisance parameters. The distributions of the statistics are shown to have an ill-defined limit as the parameter that determines the strength of the instruments tends to zero and as the correlation between the disturbances of the structural and reduced-form equations tends to plus or minus one. This makes it impossible to perform reliable inference near the point at which the limit is ill-defined. Several bootstrap procedures are proposed. They alleviate the problem and allow reliable inference when the instruments are not too weak. We also study their power properties.
ISSN:2225-1146