Identification and estimation of causal peer effects using instrumental variables

Fuente: arXiv
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Main Authors: Luo, Shanshan, Shuai, Kang, Zhang, Yechi, Li, Wei, He, Yangbo
Format: Preprint
Published: 2025
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author Luo, Shanshan
Shuai, Kang
Zhang, Yechi
Li, Wei
He, Yangbo
author_facet Luo, Shanshan
Shuai, Kang
Zhang, Yechi
Li, Wei
He, Yangbo
contents In social science researches, causal inference regarding peer effects often faces significant challenges due to homophily bias and contextual confounding. For example, unmeasured health conditions (e.g., influenza) and psychological states (e.g., happiness, loneliness) can spread among closely connected individuals, such as couples or siblings. To address these issues, we define four effect estimands for dyadic data to characterize direct effects and spillover effects. We employ dual instrumental variables to achieve nonparametric identification of these causal estimands in the presence of unobserved confounding. We then derive the efficient influence functions for these estimands under the nonparametric model. Additionally, we develop a triply robust and locally efficient estimator that remains consistent even under partial misspecification of the observed data model. The proposed robust estimators can be easily adapted to flexible approaches such as machine learning estimation methods, provided that certain rate conditions are satisfied. Finally, we illustrate our approach through simulations and an empirical application evaluating the peer effects of retirement on fluid cognitive perception among couples.
format Preprint
id arxiv_https___arxiv_org_abs_2504_05658
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Identification and estimation of causal peer effects using instrumental variables
Luo, Shanshan
Shuai, Kang
Zhang, Yechi
Li, Wei
He, Yangbo
Methodology
In social science researches, causal inference regarding peer effects often faces significant challenges due to homophily bias and contextual confounding. For example, unmeasured health conditions (e.g., influenza) and psychological states (e.g., happiness, loneliness) can spread among closely connected individuals, such as couples or siblings. To address these issues, we define four effect estimands for dyadic data to characterize direct effects and spillover effects. We employ dual instrumental variables to achieve nonparametric identification of these causal estimands in the presence of unobserved confounding. We then derive the efficient influence functions for these estimands under the nonparametric model. Additionally, we develop a triply robust and locally efficient estimator that remains consistent even under partial misspecification of the observed data model. The proposed robust estimators can be easily adapted to flexible approaches such as machine learning estimation methods, provided that certain rate conditions are satisfied. Finally, we illustrate our approach through simulations and an empirical application evaluating the peer effects of retirement on fluid cognitive perception among couples.
title Identification and estimation of causal peer effects using instrumental variables
topic Methodology
url https://arxiv.org/abs/2504.05658