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Orthogonal Integrated Conditional Moment Tests for Treatment Effect Heterogeneity

Haokun Lu, Xiaojun Song

arXiv 14 Jul 2026 · Econometrics

arXiv:2607.12622 · PDF · DOI · OpenAlex · Extracted main text

Abstract

We propose a nonparametric integrated conditional moment (ICM) test for treatment effect heterogeneity across subpopulations defined by a given covariate subvector. Under unconfoundedness, the null is recast as a conditional moment restriction based on a Neyman-orthogonal score, which reduces the first-order sensitivity of the empirical process to nuisance parameter estimation. The test statistics are constructed as continuous functionals of a marked empirical process. We establish a uniform feasible-to-oracle approximation and derive the asymptotic properties of these test statistics under the null and fixed alternatives. We further show that the test has nontrivial power against local alternatives converging to the null at the $n^{-1/2}$ rate, and develop an easy-to-implement multiplier bootstrap for feasible inference. We also develop extensions to tests of parametric CATE specifications and to settings with endogenous treatment and a binary instrument. Finally, we apply the proposed testing approach to study whether the effect of maternal smoking during pregnancy on infant birth weight varies with maternal age.

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Most heavily cited references

The works this paper leans on most, across its whole bibliography — not restricted to papers in our corpus. Ranked by composite intensity, which combines how often a work is mentioned, how many sections mention it, and how much of that falls in the main text rather than the appendix.

ReferenceIntensityMentionsSectionsMain text
1Zongwu Cai, Ying Fang, Ming Lin, and Shengfang Tang (2025) A nonparametric test of heterogeneity in conditional quantile treatment effects1.00073100%
2Yu-Chin Hsu (2017) Consistent tests for conditional treatment effects0.9285380%
3Jason Abrevaya, Yu-Chin Hsu, and Robert P Lieli (2015) Estimating conditional average treatment effects0.87482100%
4Sokbae Lee, Ryo Okui, and Yoon-Jae Whang (2017) Doubly robust uniform confidence band for the conditional average treatment effect function0.87452100%
5Keisuke Hirano, Guido W Imbens, and Geert Ridder (2003) Efficient estimation of average treatment effects using the estimated propensity score0.74417441%
6Richard K Crump, V Joseph Hotz, Guido W Imbens, and Oscar A Mitnik (2008) Nonparametric tests for treatment effect heterogeneity0.73732100%
7Qingliang Fan, Yu-Chin Hsu, Robert P Lieli, and Yichong Zhang (2022) Estimation of conditional average treatment effects with high-dimensional data0.73732100%
8Guido Imbens and Joshua Angrist (1994) Identification and estimation of local average treatment effects0.73732100%
9Pedro HC Sant’Anna (2021) Nonparametric tests for treatment effect heterogeneity with duration outcomes0.73732100%
10Heejung Bang and James M Robins (2005) Doubly robust estimation in missing data and causal inference models0.64422100%

Showing the top 10 of 41 scored citations.