Automating expert-level medical reasoning evaluation of large language models
As large language models (LLMs) become increasingly integrated into clinical decision-making, ensuring trustworthy reasoning is paramount. However, current evaluation strategies of LLMs' medical reasoning capability either suffer from unsatisfactory assessment or poor scalability, and a rigorous benchmark remains absent. To address this, we present MedThink-Bench, a benchmark designed for rigorous and scalable assessment of LLMs' medical reasoning. MedThink-Bench comprises 500 high-complexity questions spanning ten medical domains, accompanied by expert-authored, step-by-step rationales that elucidate intermediate reasoning processes. Further, we introduce LLM-w-Rationale, an evaluation framework that combines fine-grained rationale assessment with an LLM-as-a-Judge paradigm, enabling expert-level fidelity in evaluating reasoning quality while preserving scalability. Results show that LLM-w-Rationale correlates strongly with expert evaluation (Pearson coefficient up to 0.87) while requiring only 1.4% of the evaluation time. Overall, MedThink-Bench establishes a rigorous and scalable standard for evaluating medical reasoning in LLMs, advancing their safe and responsible deployment in clinical practice.
Authors
- Ninghao Liu (ORCID: https://orcid.org/0000-0002-9170-2424)
- Lindsay Welton
- Meng‐Han Tsai (ORCID: https://orcid.org/0000-0002-2466-6152)
- Jiaxi Li (ORCID: https://orcid.org/0009-0004-3678-2240)
- Yanwei Jin (ORCID: https://orcid.org/0000-0003-0905-696X)
- Meijia Song (ORCID: https://orcid.org/0009-0000-9438-3716)
- Zidu Xu (ORCID: https://orcid.org/0000-0002-6122-8426)
- Eike Schäffer (ORCID: https://orcid.org/0000-0002-4439-0069)
- Yue Xing (ORCID: https://orcid.org/0000-0001-6340-0640)
- Rui Zhang (ORCID: https://orcid.org/0000-0001-8258-3585)
- Yucheng Shi (ORCID: https://orcid.org/0000-0002-3306-0865)
- Han Yang (ORCID: https://orcid.org/0009-0000-4322-6753)
- Zirui Liu (ORCID: https://orcid.org/0000-0001-9062-6565)
- Zaifu Zhan (ORCID: https://orcid.org/0009-0007-5973-2432)
- Claudia Espinoza (ORCID: https://orcid.org/0000-0003-0336-8567)
- Shuang Zhou (ORCID: https://orcid.org/0000-0001-5535-7988)
- Yuen-Hei Chung
- Xinnie Mai
- Wenya Xie
Institutions
- University of Minnesota (US)
- University of Georgia (US)
- University of California, San Francisco (US)
- University of Virginia (US)
- University of Colorado Anschutz Medical Campus (US)
- Columbia University (US)
Publication Details
- Journal
- npj Digital Medicine
- Published
- 2025-12-06
- DOI
- https://doi.org/10.1038/s41746-025-02208-7
- Citations
- 3
- Primary Topic
- Artificial Intelligence in Healthcare and Education
- Type
- article
- Field-Weighted Citation Impact
- 1.96
Funders
- National Institutes of Health
- National Cancer Institute