Jimeng Sun
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2026
Act as you think: Reinforcing Consistent Reasoning in Medical Visual Question Answering
Songtao Jiang | Yuan Wang | Ruizhe Chen | Yan Zhang | Ruilin Luo | Bohan Lei | Yeying Jin | Sibo Song | ZhiBo Yang | Jimeng Sun | Jian Wu | Zuozhu Liu
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Songtao Jiang | Yuan Wang | Ruizhe Chen | Yan Zhang | Ruilin Luo | Bohan Lei | Yeying Jin | Sibo Song | ZhiBo Yang | Jimeng Sun | Jian Wu | Zuozhu Liu
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
While reinforcement learning from verifiable rewards (RLVR) has been proven highly effective for enhancing reasoning, its application to medical visual question answering (Med-VQA) is hampered by models producing reasoning inconsistent with either the visual evidence or the final answer. Our analysis reveals a critical flaw in RLVR training: it paradoxically encourages models to disregard visual evidence and generate answers that contradict their own reasoning. This degradation is most pronounced in specialized medical modalities (e.g., Fundus, Ultrasound) where base VLMs lack robust understanding, a failure we attribute to a flawed reward mechanism exacerbated by the scarcity of diverse training data. To tackle this, we introduce Med-Zero-17K, a large-scale dataset spanning over 30 modalities and 24 clinically relevant tasks, and the Multi-Consistency Reward (MCR) framework, which explicitly rewards both perceptual grounding and logical coherence. Extensive experiments validate our approach: integrating MCR into the RLVR framework delivers robust performance gains. This success stems from our crucial finding that rewarding internal consistency is significantly more effective than attempting to judge reasoning correctness. Furthermore, MCR proves highly versatile, exhibiting strong generalization across diverse VLM backbones, compatibility with RL algorithms like GRPO and DPO, and extending its effectiveness to 3D VQA tasks and R1-style training paradigms. Code and dataset will be released.
2025
Towards Adapting Open-Source Large Language Models for Expert-Level Clinical Note Generation
Hanyin Wang | Chufan Gao | Bolun Liu | Qiping Xu | Guleid Hussein | Mohamad El Labban | Kingsley Iheasirim | Hariprasad Reddy Korsapati | Chuck Outcalt | Jimeng Sun
Findings of the Association for Computational Linguistics: ACL 2025
Hanyin Wang | Chufan Gao | Bolun Liu | Qiping Xu | Guleid Hussein | Mohamad El Labban | Kingsley Iheasirim | Hariprasad Reddy Korsapati | Chuck Outcalt | Jimeng Sun
Findings of the Association for Computational Linguistics: ACL 2025
Proprietary Large Language Models (LLMs) such as GPT-4 and Gemini have demonstrated promising capabilities in clinical text summarization tasks. However, due to patient data privacy concerns and computational costs, many healthcare providers prefer using small, locally-hosted models over external generic LLMs. This study presents a comprehensive domain- and task-specific adaptation process for the open-source LLaMA-2 13 billion parameter model, enabling it to generate high-quality clinical notes from outpatient patient-doctor dialogues. Our process incorporates continued pre-training, supervised fine-tuning, and reinforcement learning from both AI and human feedback. We introduced a new approach, DistillDirect, for performing on-policy reinforcement learning with Gemini 1.0 Pro as the teacher model. Our resulting model, LLaMA-Clinic, can generate clinical notes comparable in quality to those authored by physicians. In a blinded physician reader study, the majority (92.8%) of individual evaluations rated the notes generated by LLaMA-Clinic as “acceptable” or higher across all three criteria: real-world readiness, completeness, and accuracy. In the more challenging “Assessment and Plan” section, LLaMA-Clinic received the same score as the notes authored by physicians. We highlight key considerations for future clinical note-generation tasks, emphasizing the importance of pre-defining a best-practice note format, rather than relying on LLMs to determine this for clinical practice.
Process-Supervised Reward Models for Verifying Clinical Note Generation: A Scalable Approach Guided by Domain Expertise
Hanyin Wang | Chufan Gao | Qiping Xu | Bolun Liu | Guleid Hussein | Hariprasad Reddy Korsapati | Mohamad El Labban | Kingsley Iheasirim | Mohamed Hassan | Gokhan Anil | Brian Bartlett | Jimeng Sun
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Hanyin Wang | Chufan Gao | Qiping Xu | Bolun Liu | Guleid Hussein | Hariprasad Reddy Korsapati | Mohamad El Labban | Kingsley Iheasirim | Mohamed Hassan | Gokhan Anil | Brian Bartlett | Jimeng Sun
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Process-supervised reward models (PRMs) excel at providing step-by-step verification for large language model (LLM) outputs in domains like mathematics and coding. However, their application to fields lacking ground-truth answers, such as clinical note generation, poses significant challenges. We introduce a novel framework for training PRMs to deliver step-level reward signals for LLM-generated clinical notes. By precisely defining meaningful “steps,” injecting realistic “errors” informed by domain expertise, and leveraging LLMs to generate process supervision data at scale, we overcome previous limitations. Our PRM, built on LLaMA-3.1 8B, consistently outperforms proprietary reasoning and non-reasoning models, achieving state-of-the-art performance on two key evaluations: (1) distinguishing gold-standard from error-containing samples with 98.8% accuracy, and (2) selecting physician-preferred clinical notes with 56.2% accuracy. We investigate critical components for effective PRM training, including optimal loss functions and data selection strategies, and present a comprehensive physician reader study identifying predictors of downstream Best-of-N performance. Our study sheds light on unlocking the potential of PRMs for diverse generative tasks across domains.
s3: You Don’t Need That Much Data to Train a Search Agent via RL
Pengcheng Jiang | Xueqiang Xu | Jiacheng Lin | Jinfeng Xiao | Zifeng Wang | Jimeng Sun | Jiawei Han
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Pengcheng Jiang | Xueqiang Xu | Jiacheng Lin | Jinfeng Xiao | Zifeng Wang | Jimeng Sun | Jiawei Han
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Retrieval-augmented generation (RAG) systems empower large language models (LLMs) to access external knowledge during inference. Recent advances have enabled LLMs to act as search agents via reinforcement learning (RL), improving information acquisition through multi-turn interactions with retrieval engines. However, existing approaches either optimize retrieval using search-only metrics (e.g., NDCG) that ignore downstream utility or fine-tune the entire LLM to jointly reason and retrieve—entangling retrieval with generation and limiting the real search utility and compatibility with frozen or proprietary models. In this work, we propose s3, a lightweight, model-agnostic framework that decouples the searcher from the generator and trains the searcher using a Gain Beyond RAG reward: the improvement in generation accuracy over naïve RAG. s3 requires only 2.4k training samples to outperform baselines trained on over 70 × more data, consistently delivering stronger downstream performance across six general QA and five medical QA benchmarks.
SECRET: Semi-supervised Clinical Trial Document Similarity Search
Trisha Das | Afrah Shafquat | Mandis Beigi | Jacob Aptekar | Jimeng Sun
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Trisha Das | Afrah Shafquat | Mandis Beigi | Jacob Aptekar | Jimeng Sun
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Clinical trials are vital for evaluation of safety and efficacy of new treatments. However, clinical trials are resource-intensive, time-consuming and expensive to conduct, where errors in trial design, reduced efficacy, and safety events can result in significant delays, financial losses, and damage to reputation. These risks underline the importance of informed and strategic decisions in trial design to mitigate these risks and improve the chances of a successful trial. Identifying similar historical trials is critical as these trials can provide an important reference for potential pitfalls and challenges including serious adverse events, dosage inaccuracies, recruitment difficulties, patient adherence issues, etc. Addressing these challenges in trial design can lead to development of more effective study protocols with optimized patient safety and trial efficiency. In this paper, we present a novel method to identify similar historical trials by summarizing clinical trial protocols and searching for similar trials based on a query trial’s protocol. Our approach significantly outperforms all baselines, achieving up to a 78% improvement in recall@1 and a 53% improvement in precision@1 over the best baseline. We also show that our method outperforms all other baselines in partial trial similarity search and zero-shot patient-trial matching, highlighting its superior utility in these tasks.
2024
PromptRE: Weakly-Supervised Document-Level Relation Extraction via Prompting-Based Data Programming
Chufan Gao | Xulin Fan | Jimeng Sun | Xuan Wang
Proceedings of the 1st Workshop on Towards Knowledgeable Language Models (KnowLLM 2024)
Chufan Gao | Xulin Fan | Jimeng Sun | Xuan Wang
Proceedings of the 1st Workshop on Towards Knowledgeable Language Models (KnowLLM 2024)
Relation extraction aims to classify the relationships between two entities into pre-defined categories. While previous research has mainly focused on sentence-level relation extraction, recent studies have expanded the scope to document-level relation extraction. Traditional relation extraction methods heavily rely on human-annotated training data, which is time-consuming and labor-intensive. To mitigate the need for manual annotation, recent weakly-supervised approaches have been developed for sentence-level relation extraction while limited work has been done on document-level relation extraction. Weakly-supervised document-level relation extraction faces significant challenges due to an imbalanced number “no relation” instances and the failure of directly probing pretrained large language models for document relation extraction. To address these challenges, we propose PromptRE, a novel weakly-supervised document-level relation extraction method that combines prompting-based techniques with data programming. Furthermore, PromptRE incorporates the label distribution and entity types as prior knowledge to improve the performance. By leveraging the strengths of both prompting and data programming, PromptRE achieves improved performance in relation classification and effectively handles the “no relation” problem. Experimental results on ReDocRED, a benchmark dataset for document-level relation extraction, demonstrate the superiority of PromptRE over baseline approaches.
Contextualized Sequence Likelihood: Enhanced Confidence Scores for Natural Language Generation
Zhen Lin | Shubhendu Trivedi | Jimeng Sun
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Zhen Lin | Shubhendu Trivedi | Jimeng Sun
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
The advent of large language models (LLMs) has dramatically advanced the state-of-the-art in numerous natural language generation tasks. For LLMs to be applied reliably, it is essential to have an accurate measure of their confidence. Currently, the most commonly used confidence score function is the likelihood of the generated sequence, which, however, conflates semantic and syntactic components. For instance, in question-answering (QA) tasks, an awkward phrasing of the correct answer might result in a lower probability prediction. Additionally, different tokens should be weighted differently depending on the context. In this work, we propose enhancing the predicted sequence probability by assigning different weights to various tokens using attention values elicited from the base LLM. By employing a validation set, we can identify the relevant attention heads, thereby significantly improving the reliability of the vanilla sequence probability confidence measure. We refer to this new score as the Contextualized Sequence Likelihood (CSL). CSL is easy to implement, fast to compute, and offers considerable potential for further improvement with task-specific prompts. Across several QA datasets and a diverse array of LLMs, CSL has demonstrated significantly higher reliability than state-of-the-art baselines in predicting generation quality, as measured by the AUROC or AUARC.
Beyond Label Attention: Transparency in Language Models for Automated Medical Coding via Dictionary Learning
John Wu | David Wu | Jimeng Sun
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
John Wu | David Wu | Jimeng Sun
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Medical coding, the translation of unstructured clinical text into standardized medical codes, is a crucial but time-consuming healthcare practice. Though large language models (LLM) could automate the coding process and improve the efficiency of such tasks, interpretability remains paramount for maintaining patient trust. Current efforts in interpretability of medical coding applications rely heavily on label attention mechanisms, which often leads to the highlighting of extraneous tokens irrelevant to the ICD code. To facilitate accurate interpretability in medical language models, this paper leverages dictionary learning that can efficiently extract sparsely activated representations from dense language model embeddings in superposition. Compared with common label attention mechanisms, our model goes beyond token-level representations by building an interpretable dictionary which enhances the mechanistic-based explanations for each ICD code prediction, even when the highlighted tokens are medically irrelevant. We show that dictionary features are human interpretable, can elucidate the hidden meanings of upwards of 90% of medically irrelevant tokens, and steer model behavior.
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Co-authors
- Chufan Gao 3
- Guleid Hussein 2
- Kingsley Iheasirim 2
- Hariprasad Reddy Korsapati 2
- Mohamad El Labban 2
- Bolun Liu 2
- Hanyin Wang 2
- Qiping Xu 2
- Gokhan Anil 1
- Jacob Aptekar 1
- Brian Bartlett 1
- Mandis Beigi 1
- Ruizhe Chen 1
- Trisha Das 1
- Xulin Fan 1
- Jiawei Han 1
- Mohamed Hassan 1
- Pengcheng Jiang 1
- Songtao Jiang 1
- Yeying Jin 1
- Bohan Lei 1
- Jiacheng Lin 1
- Zhen Lin 1
- Zuozhu Liu 1
- Ruilin Luo 1
- Chuck Outcalt 1
- Afrah Shafquat 1
- Sibo Song 1
- Shubhendu Trivedi 1
- Xuan Wang 1
- Yuan Wang 1
- Zifeng Wang 1
- David Wu 1
- Jian Wu 1
- John Wu 1
- Jinfeng Xiao 1
- Xueqiang Xu 1
- ZhiBo Yang 1
- Yan Zhang 1