Agentic Reward Modeling for Medical Reasoning

Hang Zhang, Ruheng Wang, Yuelyu Ji, Min Gu Kwak, Xizhi Wu, Chenyu Li, Li Zhang, Wenqi Shi, Yifan Peng, Yanshan Wang


Abstract
Large language models have achieved strong performance on medical reasoning benchmarks, yet their deployment in clinical settings demands rigorous verification to ensure factual accuracy. While reward models offer a scalable approach for reasoning trace verification, existing methods face two limitations: they produce only scalar reward values without explicit justification, and they rely on single-pass retrieval that precludes adaptive knowledge access as verification unfolds. We introduce Med-TIV, an agentic framework that addresses these limitations by training medical reward models to iteratively query external medical evidence during evaluation. Our approach combines tool-augmented verification with an iterative reinforcement learning paradigm that requires only trace-level supervision, alongside an adaptive curriculum mechanism that dynamically adjusts training data distribution. Across four medical reasoning benchmarks, Med-TIV achieves substantial gains over existing methods, improving MedQA accuracy by 23.5% and MedXpertQA by 32.0% relative to the base generator. Crucially, Med-TIV demonstrates an 8× reduction in sampling budget compared to prior reward model baselines. These findings establish that agentic medical reward modeling offers a principled path toward more reliable medical reasoning systems.
Anthology ID:
2026.findings-emnlp.766
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
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
16152–16168
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.766/
DOI:
Bibkey:
Cite (ACL):
Hang Zhang, Ruheng Wang, Yuelyu Ji, Min Gu Kwak, Xizhi Wu, Chenyu Li, Li Zhang, Wenqi Shi, Yifan Peng, and Yanshan Wang. 2026. Agentic Reward Modeling for Medical Reasoning. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 16152–16168, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Agentic Reward Modeling for Medical Reasoning (Zhang et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.766.pdf