Semiparametric sensitivity analysis: unmeasured confounding in observational studies

Fuente: arXiv
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Main Authors: Nabi, Razieh, Bonvini, Matteo, Kennedy, Edward H., Huang, Ming-Yueh, Smid, Marcela, Scharfstein, Daniel O.
Format: Preprint
Published: 2021
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author Nabi, Razieh
Bonvini, Matteo
Kennedy, Edward H.
Huang, Ming-Yueh
Smid, Marcela
Scharfstein, Daniel O.
author_facet Nabi, Razieh
Bonvini, Matteo
Kennedy, Edward H.
Huang, Ming-Yueh
Smid, Marcela
Scharfstein, Daniel O.
contents Establishing cause-effect relationships from observational data often relies on untestable assumptions. It is crucial to know whether, and to what extent, the conclusions drawn from non-experimental studies are robust to potential unmeasured confounding. In this paper, we focus on the average causal effect (ACE) as our target of inference. We generalize the sensitivity analysis approach developed by Robins et al. (2000), Franks et al. (2020), and Zhou and Yao (2023). We use semiparametric theory to derive the non-parametric efficient influence function of the ACE, for fixed sensitivity parameters. We use this influence function to construct a one-step, split sample, truncated estimator of the ACE. Our estimator depends on semiparametric models for the distribution of the observed data; importantly, these models do not impose any restrictions on the values of sensitivity analysis parameters. We establish sufficient conditions ensuring that our estimator has root-n asymptotics. We use our methodology to evaluate the causal effect of smoking during pregnancy on birth weight. We also evaluate the performance of estimation procedure in a simulation study.
format Preprint
id arxiv_https___arxiv_org_abs_2104_08300
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Semiparametric sensitivity analysis: unmeasured confounding in observational studies
Nabi, Razieh
Bonvini, Matteo
Kennedy, Edward H.
Huang, Ming-Yueh
Smid, Marcela
Scharfstein, Daniel O.
Methodology
Establishing cause-effect relationships from observational data often relies on untestable assumptions. It is crucial to know whether, and to what extent, the conclusions drawn from non-experimental studies are robust to potential unmeasured confounding. In this paper, we focus on the average causal effect (ACE) as our target of inference. We generalize the sensitivity analysis approach developed by Robins et al. (2000), Franks et al. (2020), and Zhou and Yao (2023). We use semiparametric theory to derive the non-parametric efficient influence function of the ACE, for fixed sensitivity parameters. We use this influence function to construct a one-step, split sample, truncated estimator of the ACE. Our estimator depends on semiparametric models for the distribution of the observed data; importantly, these models do not impose any restrictions on the values of sensitivity analysis parameters. We establish sufficient conditions ensuring that our estimator has root-n asymptotics. We use our methodology to evaluate the causal effect of smoking during pregnancy on birth weight. We also evaluate the performance of estimation procedure in a simulation study.
title Semiparametric sensitivity analysis: unmeasured confounding in observational studies
topic Methodology
url https://arxiv.org/abs/2104.08300