The Annals of Applied Statistics

Covariate balancing propensity score for a continuous treatment: Application to the efficacy of political advertisements

Christian Fong, Chad Hazlett, and Kosuke Imai

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Propensity score matching and weighting are popular methods when estimating causal effects in observational studies. Beyond the assumption of unconfoundedness, however, these methods also require the model for the propensity score to be correctly specified. The recently proposed covariate balancing propensity score (CBPS) methodology increases the robustness to model misspecification by directly optimizing sample covariate balance between the treatment and control groups. In this paper, we extend the CBPS to a continuous treatment. We propose the covariate balancing generalized propensity score (CBGPS) methodology, which minimizes the association between covariates and the treatment. We develop both parametric and nonparametric approaches and show their superior performance over the standard maximum likelihood estimation in a simulation study. The CBGPS methodology is applied to an observational study, whose goal is to estimate the causal effects of political advertisements on campaign contributions. We also provide open-source software that implements the proposed methods.

Article information

Ann. Appl. Stat. Volume 12, Number 1 (2018), 156-177.

Received: January 2017
Revised: June 2017
First available in Project Euclid: 9 March 2018

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Causal inference covariate balance generalized propensity score inverse-probability weighting treatment effect


Fong, Christian; Hazlett, Chad; Imai, Kosuke. Covariate balancing propensity score for a continuous treatment: Application to the efficacy of political advertisements. Ann. Appl. Stat. 12 (2018), no. 1, 156--177. doi:10.1214/17-AOAS1101.

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