Principal stratification with continuous treatments and continuous post-treatment variables

Fuente: arXiv
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Autori principali: Antonelli, Joseph, Wu, Minxuan, Mealli, Fabrizia, Beck, Brenden, Mattei, Alessandra
Natura: Preprint
Pubblicazione: 2023
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author Antonelli, Joseph
Wu, Minxuan
Mealli, Fabrizia
Beck, Brenden
Mattei, Alessandra
author_facet Antonelli, Joseph
Wu, Minxuan
Mealli, Fabrizia
Beck, Brenden
Mattei, Alessandra
contents Principal stratification (PS) is a commonly used approach for understanding the mechanisms through which a treatment affects an outcome. The goal of this work is to extend the PS framework to studies with continuous treatments, which introduces a number of both challenges and opportunities in terms of defining causal effects and performing inference. This manuscript provides multiple key methodological contributions: 1) we introduce principal causal estimands for continuous treatments that provide insights into different causal mechanisms, 2) we show that nonparametric identification is possible under a principal ignorability assumption, but only under a restrictive assumption on the joint distribution of potential mediators, which can be dropped under mild parametric assumptions, 3) we utilize nonparametric Bayesian models for the joint distribution of the potential mediating variables to ensure our approach is robust to model misspecification, and 4) we provide theoretical justification for utilizing an outcome model to identify the joint distribution of the potential mediating variables, and show that this is only possible if a principal ignorability assumption is violated. Lastly, we apply our methodology to a novel study of the relationship between the economy and arrest rates, and how this is potentially mediated by police capacity.
format Preprint
id arxiv_https___arxiv_org_abs_2309_14486
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Principal stratification with continuous treatments and continuous post-treatment variables
Antonelli, Joseph
Wu, Minxuan
Mealli, Fabrizia
Beck, Brenden
Mattei, Alessandra
Methodology
Applications
Principal stratification (PS) is a commonly used approach for understanding the mechanisms through which a treatment affects an outcome. The goal of this work is to extend the PS framework to studies with continuous treatments, which introduces a number of both challenges and opportunities in terms of defining causal effects and performing inference. This manuscript provides multiple key methodological contributions: 1) we introduce principal causal estimands for continuous treatments that provide insights into different causal mechanisms, 2) we show that nonparametric identification is possible under a principal ignorability assumption, but only under a restrictive assumption on the joint distribution of potential mediators, which can be dropped under mild parametric assumptions, 3) we utilize nonparametric Bayesian models for the joint distribution of the potential mediating variables to ensure our approach is robust to model misspecification, and 4) we provide theoretical justification for utilizing an outcome model to identify the joint distribution of the potential mediating variables, and show that this is only possible if a principal ignorability assumption is violated. Lastly, we apply our methodology to a novel study of the relationship between the economy and arrest rates, and how this is potentially mediated by police capacity.
title Principal stratification with continuous treatments and continuous post-treatment variables
topic Methodology
Applications
url https://arxiv.org/abs/2309.14486