Understanding Training Data Attribution in RLVR: From the Perspective of Causal Inference

Chi Zhang, Jian Zhao, Wei Wang, Kai Wang, Yao Zhao, Xuelong Li


Abstract
Training data attribution is increasingly used to filter, reweight, and prioritize rollouts in reinforcement learning with verifiable rewards (RLVR). However, these interventions often assume that individual samples, transitions, or trajectories can be attributed independently of the other data used in the same update. We show that this assumption is not merely a property of the attribution estimator, but a structural property of the training objective. We recast training data attribution as individual treatment effect estimation and use the Stable Unit Treatment Value Assumption (SUTVA) to determine when a proposed attribution unit is well-defined. This yields a simple criterion that attribution is only valid at the level where the algorithm assigns a stable contribution to that unit. Applying this criterion to RLVR, we show that the PPO objective admits trajectory-level attribution, whereas naive trajectory-only attribution is not well-defined for GRPO unless peer context is modeled. Experimental results support this distinction and provide preliminary evidence for group-level attribution under GRPO.
Anthology ID:
2026.findings-emnlp.2023
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
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SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
43042–43056
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URL:
https://aclanthology.org/2026.findings-emnlp.2023/
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Cite (ACL):
Chi Zhang, Jian Zhao, Wei Wang, Kai Wang, Yao Zhao, and Xuelong Li. 2026. Understanding Training Data Attribution in RLVR: From the Perspective of Causal Inference. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 43042–43056, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Understanding Training Data Attribution in RLVR: From the Perspective of Causal Inference (Zhang et al., Findings 2026)
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https://aclanthology.org/2026.findings-emnlp.2023.pdf