MedCaseReasoning: Evaluating and learning diagnostic reasoning from
  clinical case reports
Authors: name: Kevin Wu, name: Eric Wu, name: Rahul Thapa, name: Kevin Wei, name: Angela Zhang, name: Arvind Suresh, name: Jacqueline J. Tao, name: Min Woo Sun, name: Alejandro Lozano, name: James Zou

Doctors and patients alike increasingly use Large Language Models (LLMs) to
diagnose clinical cases. However, unlike domains such as math or coding, where
correctness can be objectively defined by the final answer, medical diagnosis
requires both the outcome and the reasoning process to be accurate. Currently,
widely used medical benchmarks like MedQA and MMLU assess only accuracy in the
final answer, overlooking the quality and faithfulness of the clinical
reasoning process. To address this limitation, we introduce MedCaseReasoning,
the first open-access dataset for evaluating LLMs on their ability to align
with clinician-authored diagnostic reasoning. The dataset includes 14,489
diagnostic question-and-answer cases, each paired with detailed reasoning
statements derived from open-access medical case reports. We evaluate
state-of-the-art reasoning LLMs on MedCaseReasoning and find significant
shortcomings in their diagnoses and reasoning: for instance, the top-performing
open-source model, DeepSeek-R1, achieves only 48% 10-shot diagnostic accuracy
and mentions only 64% of the clinician reasoning statements (recall). However,
we demonstrate that fine-tuning LLMs on the reasoning traces derived from
MedCaseReasoning significantly improves diagnostic accuracy and clinical
reasoning recall by an average relative gain of 29% and 41%, respectively. The
open-source dataset, code, and models are available at
https://github.com/kevinwu23/Stanford-MedCaseReasoning.