A Cautionary Tale on Integrating Studies with Disparate Outcome Measures for Causal Inference

Fuente: arXiv
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Autori principali: Parikh, Harsh, Nguyen, Trang Quynh, Stuart, Elizabeth A., Rudolph, Kara E., Miles, Caleb H.
Natura: Preprint
Pubblicazione: 2025
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author Parikh, Harsh
Nguyen, Trang Quynh
Stuart, Elizabeth A.
Rudolph, Kara E.
Miles, Caleb H.
author_facet Parikh, Harsh
Nguyen, Trang Quynh
Stuart, Elizabeth A.
Rudolph, Kara E.
Miles, Caleb H.
contents Data integration approaches are increasingly used to enhance the efficiency and generalizability of studies. However, a key limitation of these methods is the assumption that outcome measures are identical across datasets -- an assumption that often does not hold in practice. Consider the following opioid use disorder (OUD) studies: the XBOT trial and the POAT study, both evaluating the effect of medications for OUD on withdrawal symptom severity (not the primary outcome of either trial). While XBOT measures withdrawal severity using the subjective opiate withdrawal scale, POAT uses the clinical opiate withdrawal scale. We analyze this realistic yet challenging setting where outcome measures differ across studies and where neither study records both types of outcomes. Our paper studies whether and when integrating studies with disparate outcome measures leads to efficiency gains. We introduce three sets of assumptions -- with varying degrees of strength -- linking both outcome measures. Our theoretical and empirical results highlight a cautionary tale: integration can improve asymptotic efficiency only under the strongest assumption linking the outcomes. However, misspecification of this assumption leads to bias. In contrast, a milder assumption may yield finite-sample efficiency gains, yet these benefits diminish as sample size increases. We illustrate these trade-offs via a case study integrating the XBOT and POAT datasets to estimate the comparative effect of two medications for opioid use disorder on withdrawal symptoms. By systematically varying the assumptions linking the SOW and COW scales, we show potential efficiency gains and the risks of bias. Our findings emphasize the need for careful assumption selection when fusing datasets with differing outcome measures, offering guidance for researchers navigating this common challenge in modern data integration.
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id arxiv_https___arxiv_org_abs_2505_11014
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Cautionary Tale on Integrating Studies with Disparate Outcome Measures for Causal Inference
Parikh, Harsh
Nguyen, Trang Quynh
Stuart, Elizabeth A.
Rudolph, Kara E.
Miles, Caleb H.
Methodology
Machine Learning
Econometrics
Data integration approaches are increasingly used to enhance the efficiency and generalizability of studies. However, a key limitation of these methods is the assumption that outcome measures are identical across datasets -- an assumption that often does not hold in practice. Consider the following opioid use disorder (OUD) studies: the XBOT trial and the POAT study, both evaluating the effect of medications for OUD on withdrawal symptom severity (not the primary outcome of either trial). While XBOT measures withdrawal severity using the subjective opiate withdrawal scale, POAT uses the clinical opiate withdrawal scale. We analyze this realistic yet challenging setting where outcome measures differ across studies and where neither study records both types of outcomes. Our paper studies whether and when integrating studies with disparate outcome measures leads to efficiency gains. We introduce three sets of assumptions -- with varying degrees of strength -- linking both outcome measures. Our theoretical and empirical results highlight a cautionary tale: integration can improve asymptotic efficiency only under the strongest assumption linking the outcomes. However, misspecification of this assumption leads to bias. In contrast, a milder assumption may yield finite-sample efficiency gains, yet these benefits diminish as sample size increases. We illustrate these trade-offs via a case study integrating the XBOT and POAT datasets to estimate the comparative effect of two medications for opioid use disorder on withdrawal symptoms. By systematically varying the assumptions linking the SOW and COW scales, we show potential efficiency gains and the risks of bias. Our findings emphasize the need for careful assumption selection when fusing datasets with differing outcome measures, offering guidance for researchers navigating this common challenge in modern data integration.
title A Cautionary Tale on Integrating Studies with Disparate Outcome Measures for Causal Inference
topic Methodology
Machine Learning
Econometrics
url https://arxiv.org/abs/2505.11014