The Role of Measured Covariates in Assessing Sensitivity to Unmeasured Confounding

Fuente: arXiv
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Main Authors: Dalal, Abhinandan, Horng, Iris, Feng, Yang, Small, Dylan S.
Format: Preprint
Published: 2026
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author Dalal, Abhinandan
Horng, Iris
Feng, Yang
Small, Dylan S.
author_facet Dalal, Abhinandan
Horng, Iris
Feng, Yang
Small, Dylan S.
contents Sensitivity analysis is widely used to assess the robustness of causal conclusions in observational studies, yet its interaction with the structure of measured covariates is often overlooked. When latent confounders cannot be directly adjusted for and are instead controlled using proxy variables, strong associations between exposure and measured proxies can amplify sensitivity to residual confounding. We formalize this phenomenon in linear regression settings by showing that a simple ratio involving the exposure model coefficient and residual exposure variance provides an observable measure of this increased sensitivity. Applying our framework to smoking and lung cancer, we document how growing socioeconomic stratification in smoking behavior over time leads to heightened sensitivity to unmeasured confounding in more recent data. These results highlight the importance of multicollinearity when interpreting sensitivity analyses based on proxy adjustment.
format Preprint
id arxiv_https___arxiv_org_abs_2602_14414
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle The Role of Measured Covariates in Assessing Sensitivity to Unmeasured Confounding
Dalal, Abhinandan
Horng, Iris
Feng, Yang
Small, Dylan S.
Methodology
Econometrics
Applications
Sensitivity analysis is widely used to assess the robustness of causal conclusions in observational studies, yet its interaction with the structure of measured covariates is often overlooked. When latent confounders cannot be directly adjusted for and are instead controlled using proxy variables, strong associations between exposure and measured proxies can amplify sensitivity to residual confounding. We formalize this phenomenon in linear regression settings by showing that a simple ratio involving the exposure model coefficient and residual exposure variance provides an observable measure of this increased sensitivity. Applying our framework to smoking and lung cancer, we document how growing socioeconomic stratification in smoking behavior over time leads to heightened sensitivity to unmeasured confounding in more recent data. These results highlight the importance of multicollinearity when interpreting sensitivity analyses based on proxy adjustment.
title The Role of Measured Covariates in Assessing Sensitivity to Unmeasured Confounding
topic Methodology
Econometrics
Applications
url https://arxiv.org/abs/2602.14414