On the role of surrogates in the efficient estimation of treatment effects with limited outcome data

Fuente: arXiv
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Main Authors: Kallus, Nathan, Mao, Xiaojie
Format: Preprint
Published: 2020
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author Kallus, Nathan
Mao, Xiaojie
author_facet Kallus, Nathan
Mao, Xiaojie
contents In many experimental and observational studies, the outcome of interest is often difficult or expensive to observe, reducing effective sample sizes for estimating average treatment effects (ATEs) even when identifiable. We study how incorporating data on units for which only surrogate outcomes not of primary interest are observed can increase the precision of ATE estimation. We refrain from imposing stringent surrogacy conditions, which permit surrogates as perfect replacements for the target outcome. Instead, we supplement the available, albeit limited, observations of the target outcome with abundant observations of surrogate outcomes, without any assumptions beyond unconfounded treatment assignment and missingness and corresponding overlap conditions. To quantify the potential gains, we derive the difference in efficiency bounds on ATE estimation with and without surrogates, both when an overwhelming or comparable number of units have missing outcomes. We develop robust ATE estimation and inference methods that realize these efficiency gains. We empirically demonstrate the gains by studying long-term-earning effects of job training.
format Preprint
id arxiv_https___arxiv_org_abs_2003_12408
institution arXiv
publishDate 2020
record_format arxiv
spellingShingle On the role of surrogates in the efficient estimation of treatment effects with limited outcome data
Kallus, Nathan
Mao, Xiaojie
Machine Learning
Methodology
In many experimental and observational studies, the outcome of interest is often difficult or expensive to observe, reducing effective sample sizes for estimating average treatment effects (ATEs) even when identifiable. We study how incorporating data on units for which only surrogate outcomes not of primary interest are observed can increase the precision of ATE estimation. We refrain from imposing stringent surrogacy conditions, which permit surrogates as perfect replacements for the target outcome. Instead, we supplement the available, albeit limited, observations of the target outcome with abundant observations of surrogate outcomes, without any assumptions beyond unconfounded treatment assignment and missingness and corresponding overlap conditions. To quantify the potential gains, we derive the difference in efficiency bounds on ATE estimation with and without surrogates, both when an overwhelming or comparable number of units have missing outcomes. We develop robust ATE estimation and inference methods that realize these efficiency gains. We empirically demonstrate the gains by studying long-term-earning effects of job training.
title On the role of surrogates in the efficient estimation of treatment effects with limited outcome data
topic Machine Learning
Methodology
url https://arxiv.org/abs/2003.12408