EconBase
← All papers

Attenuated Heterogeneity in Fixed-Effects Causal Forests, and a Cross-Fitted Correction

Harry Aytug

arXiv 24 Jul 2026 · Econometrics

arXiv:2607.22896 · PDF · Extracted main text

Abstract

Causal forests that estimate conditional average treatment effects by averaging honest leaf-level effects across trees are widely used in fixed-effects panel settings. We show that this averaging systematically attenuates the estimated heterogeneity: the raw prediction behaves like a + b*tau(x) with slope b < 1, so the spread of the CATEs is compressed toward the average effect, and the additive recentering used to report an unbiased average treatment effect does not fix it. Benchmarking against a similarity-weight generalized random forest on the same within-transformed signal, we find both estimators attenuate but the leaf-averaging construction attenuates materially more. We characterize how b moves with the design, worsening with lower signal-to-noise, smaller panels, and higher dimension; this diagnosis is our main contribution. As a remedy we adapt the best-linear-predictor calibration of Chernozhukov et al., estimating the de-attenuation slope out-of-bag so that it is self-contained within the observational panel and asymptotically inert under a homogeneous effect. In simulations the correction cuts CATE mean-squared error by 25-42% relative to the recentering default; on a standard county minimum-wage panel the attenuation is present but mild and the correction restores the imposed spread. We ship the method in the causalfe Python package.

Citation extraction

11
references
30
in-text mentions
11
distinct cited
0
self-citations
6,447
main-text words

appendix boundary found by none_found · 100% of the source is main text. Read the extracted text to check this.

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
1Victor Chernozhukov, Mert Demirer, Esther Duflo, and Iván Fernández-… Fisher–schultz lecture: Generic machine learning inference on heterogeneous treatment effects in randomized experiments, with an…1.00053100%
2Susan Athey, Julie Tibshirani, and Stefan Wager (2019) Generalized random forests0.84333100%
3Brantly Callaway and Pedro H. C. Sant'Anna (2020) Difference-in-differences with multiple time periods0.84333100%
4Stefan Wager and Susan Athey (2017) Estimation and inference of heterogeneous treatment effects using random forests0.84333100%
5Susan Athey and Stefan Wager (2019) Estimating treatment effects with causal forests: An application0.81142100%
6Susan Athey and Guido Imbens (2016) Recursive partitioning for heterogeneous causal effects0.73732100%
7Lars van der Laan, Ernesto Ulloa-Pérez, Marco Carone, and Alex Luedtke (2023) Causal isotonic calibration for heterogeneous treatment effects0.73732100%
8Mark A. C. Kattenberg, Bas J. Scheer, and Jurre H. Thiel (2023) Causal forests with fixed effects for treatment effect heterogeneity in difference-in-differences0.64422100%
9Yan Leng and Drew Dimmery (2022) Calibration of heterogeneous treatment effects in randomized experiments0.51121100%
10Evelina Gavrilova, Audun Langrgen, and Floris T. Zoutman (2025) Difference-in-difference causal forests, with an application to payroll tax incidence in norway0.40511100%

Showing the top 10 of 11 scored citations.