BrainMed-8B-SFT

Full-parameter supervised fine-tune of FreedomIntelligence/HuatuoGPT-o1-8B on Williamsanderson/MedReason-MedO1-Reasoning-46K, a union of KG-grounded MedReason reasoning traces and verifier-checked medical-o1 traces.

  • Parameters: 8,030,261,248 (8.03B) - full weights, not an adapter
  • Precision: BF16
  • Recipe: MedReason (arXiv:2504.00993) - lr 5e-6, effective batch 128, 3 epochs, cosine schedule with 5% warmup, weight decay 0.1, DeepSpeed ZeRO-3, bf16
  • Weights obtained by: lowest held-out validation loss (val loss 0.7557 at optimizer step 1041)

Output format

The model is trained to reason inside <think>...</think> and answer inside <answer>...</answer>, under this system prompt:

You are a medical reasoning assistant. Work through the clinical problem step by step inside <think>...</think>, grounding every step in established medical knowledge, then give the final, complete answer inside <answer>...</answer>.

Evaluation

Benchmark n Accuracy
medbullets_op4 308 58.77
medbullets_op5 308 56.82
medmcqa_val 4183 61.2
medqa_4opt 1273 72.11
medxpertqa 1449 18.08
pubmedqa_test 1000 77.1

Scored with the MedReason evaluation harness (greedy decoding, strict answer prompt, max(head, tail) extraction) on the benchmark files shipped by the MedReason and HuatuoGPT-o1 repositories - no benchmark was rebuilt or resampled.

Data integrity

Training rows: 44,351.

Rows overlapping the evaluation benchmarks were kept, matching the upstream setting under which the published comparison tables were produced. The overlap was measured and is declared below rather than removed; the evaluation therefore reports a clean-subset score alongside the raw one, and the clean figure is the unbiased estimate.

Benchmark items overlapping training rows
hle_med 103 30 (29.13%)
medbullets_op4 308 35 (11.36%)
medbullets_op5 308 35 (11.36%)
medqa_4opt 1273 1 (0.08%)
medqa_5opt 1273 1 (0.08%)
medxpertqa 1449 15 (1.04%)
mmlu_pro_medical 1535 340 (22.15%)

This overlap originates upstream: the MedReason corpus derives reasoning traces from MMLU-medical, MedXpertQA and Humanity's Last Exam, three sets it also evaluates on.

Answer-format alignment was applied to 17,083 rows (38.52%): a canonical The answer is X. was appended where the letter was unambiguously recoverable from options already present in the question. Questions and reasoning traces are byte-identical to the source.

Intended use

Research and decision support. Not a medical device; not for autonomous clinical use.

Citation

@misc{wu2025medreason,
  title={MedReason: Eliciting Factual Medical Reasoning Steps in LLMs via Knowledge Graphs},
  author={Wu, Juncheng and others}, year={2025}, eprint={2504.00993}, archivePrefix={arXiv}
}
Downloads last month
-
Safetensors
Model size
8B params
Tensor type
BF16
·
Inference Providers NEW
This model isn't deployed by any Inference Provider. 🙋 Ask for provider support

Model tree for BrainHealthAI/BrainMed-8B-SFT

Paper for BrainHealthAI/BrainMed-8B-SFT