Long-term Causal Inference Under Persistent Confounding via Data Combination

Fuente: arXiv
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Autori principali: Imbens, Guido, Kallus, Nathan, Mao, Xiaojie, Wang, Yuhao
Natura: Preprint
Pubblicazione: 2022
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author Imbens, Guido
Kallus, Nathan
Mao, Xiaojie
Wang, Yuhao
author_facet Imbens, Guido
Kallus, Nathan
Mao, Xiaojie
Wang, Yuhao
contents We study the identification and estimation of long-term treatment effects when both experimental and observational data are available. Since the long-term outcome is observed only after a long delay, it is not measured in the experimental data, but only recorded in the observational data. However, both types of data include observations of some short-term outcomes. In this paper, we uniquely tackle the challenge of persistent unmeasured confounders, i.e., some unmeasured confounders that can simultaneously affect the treatment, short-term outcomes and the long-term outcome, noting that they invalidate identification strategies in previous literature. To address this challenge, we exploit the sequential structure of multiple short-term outcomes, and develop three novel identification strategies for the average long-term treatment effect. We further propose three corresponding estimators and prove their asymptotic consistency and asymptotic normality. We finally apply our methods to estimate the effect of a job training program on long-term employment using semi-synthetic data. We numerically show that our proposals outperform existing methods that fail to handle persistent confounders.
format Preprint
id arxiv_https___arxiv_org_abs_2202_07234
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Long-term Causal Inference Under Persistent Confounding via Data Combination
Imbens, Guido
Kallus, Nathan
Mao, Xiaojie
Wang, Yuhao
Methodology
Econometrics
Machine Learning
We study the identification and estimation of long-term treatment effects when both experimental and observational data are available. Since the long-term outcome is observed only after a long delay, it is not measured in the experimental data, but only recorded in the observational data. However, both types of data include observations of some short-term outcomes. In this paper, we uniquely tackle the challenge of persistent unmeasured confounders, i.e., some unmeasured confounders that can simultaneously affect the treatment, short-term outcomes and the long-term outcome, noting that they invalidate identification strategies in previous literature. To address this challenge, we exploit the sequential structure of multiple short-term outcomes, and develop three novel identification strategies for the average long-term treatment effect. We further propose three corresponding estimators and prove their asymptotic consistency and asymptotic normality. We finally apply our methods to estimate the effect of a job training program on long-term employment using semi-synthetic data. We numerically show that our proposals outperform existing methods that fail to handle persistent confounders.
title Long-term Causal Inference Under Persistent Confounding via Data Combination
topic Methodology
Econometrics
Machine Learning
url https://arxiv.org/abs/2202.07234