TY - JOUR
T1 - Decomposition analysis to identify intervention targets for reducing disparities
AU - Jackson, John W.
AU - VanderWeele, Tyler J.
N1 - Funding Information:
Submitted March 17, 2017; accepted July 24, 2018. From the aDepartment of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD; bDepartment of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD; cDepart-ment of Epidemiology, Harvard T.H. Chan School of Public Health, Bos-ton, MA; and dDepartment of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA. Data and Code Availability: https://github.com/jwjackson/SuppMaterials. John Jackson was partly funded by the Alonzo Smythe Yerby Fellowship, and Tyler J. VanderWeele was funded by the National Institutes of health grant ES017876. The authors report no conflicts of interest. Supplemental digital content is available through direct URL citations in the HTML and PDF versions of this article (www.epidem.com). Correspondence: John W. Jackson, Departments of Epidemiology and Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD. E-mail: john.jackson@jhu.edu.
Publisher Copyright:
Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.
PY - 2018
Y1 - 2018
N2 - There has been considerable interest in using decomposition methods in epidemiology (mediation analysis) and economics (Oaxaca-Blinder decomposition) to understand how health disparities arise and how they might change upon intervention. It has not been clear when estimates from the Oaxaca-Blinder decomposition can be interpreted causally because its implementation does not explicitly address potential confounding of target variables. While mediation analysis does explicitly adjust for confounders of target variables, it typically does so in a way that effectively entails equalizing confounders across racial groups, which may not reflect the intended intervention. Revisiting prior analyses in the National Longitudinal Survey of Youth on disparities in wages, unemployment, incarceration, and overall health with test scores, taken as a proxy for educational attainment, as a target intervention, we propose and demonstrate a novel decomposition that controls for confounders of test scores (e.g., measures of childhood socioeconomic status [SES]) while leaving their association with race intact. We compare this decomposition with others that use standardization (to equalize childhood SES [the confounders] alone), mediation analysis (to equalize test scores within levels of childhood SES), and one that equalizes both childhood SES and test scores. We also show how these decompositions, including our novel proposals, are equivalent to implementations of the Oaxaca-Blinder decomposition but provide a more formal causal interpretation for these decompositions.
AB - There has been considerable interest in using decomposition methods in epidemiology (mediation analysis) and economics (Oaxaca-Blinder decomposition) to understand how health disparities arise and how they might change upon intervention. It has not been clear when estimates from the Oaxaca-Blinder decomposition can be interpreted causally because its implementation does not explicitly address potential confounding of target variables. While mediation analysis does explicitly adjust for confounders of target variables, it typically does so in a way that effectively entails equalizing confounders across racial groups, which may not reflect the intended intervention. Revisiting prior analyses in the National Longitudinal Survey of Youth on disparities in wages, unemployment, incarceration, and overall health with test scores, taken as a proxy for educational attainment, as a target intervention, we propose and demonstrate a novel decomposition that controls for confounders of test scores (e.g., measures of childhood socioeconomic status [SES]) while leaving their association with race intact. We compare this decomposition with others that use standardization (to equalize childhood SES [the confounders] alone), mediation analysis (to equalize test scores within levels of childhood SES), and one that equalizes both childhood SES and test scores. We also show how these decompositions, including our novel proposals, are equivalent to implementations of the Oaxaca-Blinder decomposition but provide a more formal causal interpretation for these decompositions.
KW - Causal inference
KW - Health disparity
KW - Inequity
KW - Interven-tional effects
KW - Mediation analysis
KW - Oaxaca Blinder decomposition
KW - Path analysis
KW - Path-specific effect
KW - Standardization
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U2 - 10.1097/EDE.0000000000000901
DO - 10.1097/EDE.0000000000000901
M3 - Article
C2 - 30063540
AN - SCOPUS:85056286316
VL - 29
SP - 825
EP - 835
JO - Epidemiology
JF - Epidemiology
SN - 1044-3983
IS - 6
ER -