Testing for the Unconfoundedness Assumption Using an Instrumental Assumption

The identification of average causal effects of a treatment in observational studies is typically based either on the unconfoundedness assumption (exogeneity of the treatment) or on the availability of an instrument. When available, instruments may also be used to test for the unconfoundedness assum...

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Autores principales: de Luna Xavier, Johansson Per
Formato: Artículo
Lenguaje:English
Publicado: De Gruyter 2014-09-01
Colección:Journal of Causal Inference
Materias:
Acceso en línea:https://doi.org/10.1515/jci-2013-0011
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author de Luna Xavier
Johansson Per
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Johansson Per
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description The identification of average causal effects of a treatment in observational studies is typically based either on the unconfoundedness assumption (exogeneity of the treatment) or on the availability of an instrument. When available, instruments may also be used to test for the unconfoundedness assumption. In this paper, we present a set of assumptions on an instrumental variable which allows us to test for the unconfoundedness assumption, although they do not necessarily yield nonparametric identification of an average causal effect. We propose a test for the unconfoundedness assumption based on the instrumental assumptions introduced and give conditions under which the test has power. We perform a simulation study and apply the results to a case study where the interest lies in evaluating the effect of job practice on employment.
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spelling doaj.art-df1c854d5e014b51a38b8d49985994172022-12-21T22:01:22ZengDe GruyterJournal of Causal Inference2193-36772193-36852014-09-012218719910.1515/jci-2013-0011Testing for the Unconfoundedness Assumption Using an Instrumental Assumptionde Luna Xavier0Johansson PerDepartment of Statistics, Umeå School of Business and Economics, Umeå University, SE-90187 Umeå, SwedenThe identification of average causal effects of a treatment in observational studies is typically based either on the unconfoundedness assumption (exogeneity of the treatment) or on the availability of an instrument. When available, instruments may also be used to test for the unconfoundedness assumption. In this paper, we present a set of assumptions on an instrumental variable which allows us to test for the unconfoundedness assumption, although they do not necessarily yield nonparametric identification of an average causal effect. We propose a test for the unconfoundedness assumption based on the instrumental assumptions introduced and give conditions under which the test has power. We perform a simulation study and apply the results to a case study where the interest lies in evaluating the effect of job practice on employment.https://doi.org/10.1515/jci-2013-0011average treatment effectjob practicenonparametric identification
spellingShingle de Luna Xavier
Johansson Per
Testing for the Unconfoundedness Assumption Using an Instrumental Assumption
Journal of Causal Inference
average treatment effect
job practice
nonparametric identification
title Testing for the Unconfoundedness Assumption Using an Instrumental Assumption
title_full Testing for the Unconfoundedness Assumption Using an Instrumental Assumption
title_fullStr Testing for the Unconfoundedness Assumption Using an Instrumental Assumption
title_full_unstemmed Testing for the Unconfoundedness Assumption Using an Instrumental Assumption
title_short Testing for the Unconfoundedness Assumption Using an Instrumental Assumption
title_sort testing for the unconfoundedness assumption using an instrumental assumption
topic average treatment effect
job practice
nonparametric identification
url https://doi.org/10.1515/jci-2013-0011
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