A Test for Instrument Validity. Issue 5 (September 2015)

• Record Type: Journal Article
• Authors: Kitagawa, Toru
• Is Part Of: Econometrica. Volume 83:Issue 5(2015:Sep.)
• Page Start: 2043
• Page End: 2063
• Publication Date: 2015-09
• Subjects: Econometrics -- Periodicals; Economics, Mathematical -- Periodicals; Economics -- Periodicals; Économétrie -- Périodiques; Mathématiques économiques -- Périodiques; Économie politique -- Périodiques; 330.05
• DOI: 10.3982/ECTA11974
• Languages: English
• ISSNs: 0012-9682

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>This paper develops a specification test for instrument validity in the heterogeneous treatment effect model with a binary treatment and a discrete instrument. The strongest testable implication for instrument validity is given by the condition for nonnegativity of point‐identifiable compliers' outcome densities. Our specification test infers this testable implication using a variance‐weighted Kolmogorov–Smirnov test statistic. The test can be applied to both discrete and continuous outcome cases, and an extension of the test to settings with conditioning covariates is provided.</p> </abstract>