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Modeling Covariate Transition for Efficient Estimation of Longitudinal Treatment Effects in Randomized Experiments

Naoki Chihara, Tatsushi Oka, Yasuko Matsubara, Yasushi Sakurai, Shota Yasui

arXiv 29 May 2026 · Statistics — Methodology

arXiv:2605.31443 · PDF · DOI · OpenAlex · Extracted main text

Abstract

We present a regression-adjustment framework designed for the estimation of longitudinal treatment effects in randomized experiments under static regimes. While regression-adjustment methods are useful for variance reduction in randomized experiments by using pre-treatment covariates, they usually focus only on average effects, from which we cannot obtain valuable insights into when the effects appear and how long they continue. To address this issue, we consider intermediate outcomes and evolving post-treatment covariates over time, and we represent such dynamic trajectories using transition kernels. Furthermore, we establish the asymptotic normality and the semiparametric efficiency bound for our estimator, enabling more powerful statistical inference. Simulation studies and empirical analysis using A/B test data from a streaming platform in Japan show the practical advantages of our method.

Citation extraction

79
references
94
in-text mentions
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distinct cited
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self-citations
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main-text words

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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
1Chernozhukov, Victor and Chetverikov, Denis and Demirer, Mert and Du… Double/Debiased Machine Learning for Treatment and Structural Parameters0.84333100%
2Bloniarz, Adam and Liu, Hanzhong and Zhang, Cun-Hui and Sekhon, Jasj… Lasso adjustments of treatment effect estimates in randomized experiments0.64422100%
3Chernozhukov, Victor and Escanciano, Juan Carlos and Ichimura, Hideh… Locally Robust Semiparametric Estimation0.64422100%
4Deng, Alex and Xu, Ya and Kohavi, Ron and Walker, Toby Improving the sensitivity of online controlled experiments by utilizing pre-experiment data0.64422100%
5Freedman, David A Randomization Does Not Justify Logistic Regression0.64422100%
6Imbens, Guido W and Rubin, Donald B Causal Inference for Statistics, Social, and Biomedical Sciences: An Introduction0.64422100%
7Lewis, Randall A and Rao, Justin M The Unfavorable Economics of Measuring the Returns to Advertising0.64422100%
8Lin, Winston Agnostic notes on regression adjustments to experimental data: Reexamining Freedman’s critique0.64422100%
9Montgomery, Jacob M and Nyhan, Brendan and Torres, Michelle How Conditioning on Posttreatment Variables Can Ruin Your Experiment and What to Do about It0.64422100%
10Tsiatis, Anastasios A and Davidian, Marie and Zhang, Min and Lu, Xia… Covariate adjustment for two-sample treatment comparisons in randomized clinical trials: a principled yet flexible approach0.64422100%

Showing the top 10 of 79 scored citations.