Bounding Causal Effects with Leaky Instruments

Fuente: arXiv
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Main Authors: Watson, David S., Penn, Jordan, Gunderson, Lee M., Bravo-Hermsdorff, Gecia, Mastouri, Afsaneh, Silva, Ricardo
Format: Preprint
Published: 2024
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author Watson, David S.
Penn, Jordan
Gunderson, Lee M.
Bravo-Hermsdorff, Gecia
Mastouri, Afsaneh
Silva, Ricardo
author_facet Watson, David S.
Penn, Jordan
Gunderson, Lee M.
Bravo-Hermsdorff, Gecia
Mastouri, Afsaneh
Silva, Ricardo
contents Instrumental variables (IVs) are a popular and powerful tool for estimating causal effects in the presence of unobserved confounding. However, classical approaches rely on strong assumptions such as the $\textit{exclusion criterion}$, which states that instrumental effects must be entirely mediated by treatments. This assumption often fails in practice. When IV methods are improperly applied to data that do not meet the exclusion criterion, estimated causal effects may be badly biased. In this work, we propose a novel solution that provides $\textit{partial}$ identification in linear systems given a set of $\textit{leaky instruments}$, which are allowed to violate the exclusion criterion to some limited degree. We derive a convex optimization objective that provides provably sharp bounds on the average treatment effect under some common forms of information leakage, and implement inference procedures to quantify the uncertainty of resulting estimates. We demonstrate our method in a set of experiments with simulated data, where it performs favorably against the state of the art. An accompanying $\texttt{R}$ package, $\texttt{leakyIV}$, is available from $\texttt{CRAN}$.
format Preprint
id arxiv_https___arxiv_org_abs_2404_04446
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Bounding Causal Effects with Leaky Instruments
Watson, David S.
Penn, Jordan
Gunderson, Lee M.
Bravo-Hermsdorff, Gecia
Mastouri, Afsaneh
Silva, Ricardo
Methodology
Artificial Intelligence
Instrumental variables (IVs) are a popular and powerful tool for estimating causal effects in the presence of unobserved confounding. However, classical approaches rely on strong assumptions such as the $\textit{exclusion criterion}$, which states that instrumental effects must be entirely mediated by treatments. This assumption often fails in practice. When IV methods are improperly applied to data that do not meet the exclusion criterion, estimated causal effects may be badly biased. In this work, we propose a novel solution that provides $\textit{partial}$ identification in linear systems given a set of $\textit{leaky instruments}$, which are allowed to violate the exclusion criterion to some limited degree. We derive a convex optimization objective that provides provably sharp bounds on the average treatment effect under some common forms of information leakage, and implement inference procedures to quantify the uncertainty of resulting estimates. We demonstrate our method in a set of experiments with simulated data, where it performs favorably against the state of the art. An accompanying $\texttt{R}$ package, $\texttt{leakyIV}$, is available from $\texttt{CRAN}$.
title Bounding Causal Effects with Leaky Instruments
topic Methodology
Artificial Intelligence
url https://arxiv.org/abs/2404.04446