Cited by 313Topic ModelingInformation Retrieval and Search BehaviorArtificial Intelligence in Healthcare and Education

Benchmarking Retrieval-Augmented Generation for Medicine

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Xiong, Guangzhi, Jin, Qiao, Lu, Zhiyong, Zhang, Aidong·2024·Findings of the Association for Computational Linguistics ACL 2024

Abstract

While large language models (LLMs) have achieved state-of-the-art performance on a wide range of medical question answering (QA) tasks, they still face challenges with hallucinations and outdated knowledge.Retrievalaugmented generation (RAG) is a promising solution and has been widely adopted.However, a RAG system can involve multiple flexible components, and there is a lack of best practices regarding the optimal RAG setting for various medical purposes.To systematically evaluate such systems, we propose the Medical Information Retrieval-Augmented Generation Evaluation (MIRAGE), a first-of-its-kind benchmark including 7,663 questions from five medical QA datasets.Using MIRAGE, we conducted large-scale experiments with over 1.8 trillion prompt tokens on 41 combinations of different corpora, retrievers, and backbone LLMs through the MEDRAG toolkit introduced in this work.Overall, MEDRAG improves the accuracy of six different LLMs by up to 18% over chain-of-thought prompting, elevating the performance of GPT-3.5 and Mixtral to GPT-4level.Our results show that the combination of various medical corpora and retrievers achieves the best performance.In addition, we discovered a log-linear scaling property and the "lostin-the-middle" effects in medical RAG.We believe our comprehensive evaluations can serve as practical guidelines for implementing RAG systems for medicine 1 .

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  • LLMs have shown the ability to retrieve relevant medical texts.

    “Recently, LLMs have shown the ability to encode clinical knowledge7,8, retrieve relevant medical texts9, and perform accurate single-turn medical question-answering3,10–12.”

    From AgentClinic: a multimodal benchmark for tool-using clinical AI agents (2026) · cites this paper as [9]

    In “Question-Only Retrieval (QOR)” (page unavailable), the paper assigns retrieval to separate algorithms such as BM25 and MedCPT; it says the retrieved snippets are then prepended to the LLMs’ input. It therefore does not show LLMs themselves retrieving relevant medical texts, as the citing sentence claims. (LLM, conf=0.84)

    Checked by a reasoning model — may be wrong.

    Experimental — accuracy not yet measured
  • All analyses were performed on publicly available, de-identified benchmark datasets used in accordance with their respective licenses and terms of use.

    “All analyses were performed on publicly available, de-identified benchmark datasets—MIRAGE [23], PubMedQA [24], and the medical licensing examination questions of Katz et al. [25]—used in accordance with their respective licenses and terms of use.”

    From The economics of accuracy for medical reasoning with large language models (2026) · cites this paper as [23]

    The Question-Only Retrieval section identifies MIRAGE as a medical QA benchmark, and Appendix B provides a link to it. The paper does not establish that MIRAGE is de-identified or that the citing authors used it in accordance with its license and terms of use. (LLM, conf=0.83)

    Experimental — accuracy not yet measured
  • Without context on the MIRAGE dataset, MedGemma 27B with extended reasoning (PCCR-1024) reached 80.1% which is higher than the 73.4% accuracy reported for GPT-4 without context and matched the performance of GPT-4 with access to extensive context [23].

    “Similarly, without context on the MIRAGE datset, MedGemma 27B with extended reasoning (PCCR-1024) reached 80.1% which is higher than the 73.4% accuracy reported for GPT-4 without context and matched the performance of GPT-4 with access to extensive context [23].”
  • The context recall limitation pattern appeared in approximately 40% of cases.

    “This pattern appeared in approximately 40% of cases, underscoring retrieval challenges in medical RAG systems where the complexity of clinical terminology limits the effectiveness of standard mechanisms [57,58].”

    From Enhancing Medical Question Answering with LLMs via a Hybrid Retrieval-Augmented Generation Framework (2026) · cites this paper as [57]

    Section 6.1 discusses retrieval and reports that 79.6% of ground-truth snippets for PubMedQA* were retrieved as the top result, but it does not report a context-recall limitation in approximately 40% of cases. Searches for “40%,” “recall,” and clinical-terminology-related retrieval limitations found no passage establishing the claimed pattern; page numbers were unavailable in our copy. (LLM, conf=0.75)

    Experimental — accuracy not yet measured
  • Faithfulness errors appeared in approximately 30% of cases.

    “Such errors appeared in approximately 30% of cases, underscoring integration challenges in RAG systems where connecting retrieved facts to query-specific conclusions remain a persistent limitation [57].”

    From Enhancing Medical Question Answering with LLMs via a Hybrid Retrieval-Augmented Generation Framework (2026) · cites this paper as [57]

    The benchmark tables report medical question-answering accuracy, not the frequency of faithfulness errors. The Limitations section says MEDRAG’s generated rationales remain to be evaluated. Searches for faithfulness errors and a 30% error rate found no passage supporting the attributed figure. (LLM, conf=0.76)

    Experimental — accuracy not yet measured

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Cited by

Sorted by citations

Authors
Xiong, G., Jin, Q., Lu, Z., & Zhang, A.
Affiliations
National Institutes of Health (US)
Venue
Findings of the Association for Computational Linguistics ACL 2024
Published
2024
Pages
6233-6251
OpenAlex
W4402670290
Cited by
310
References
0
Citations by year
2026: 142 · 2025: 144 · 2024: 24
FWCI
91.48
Type
conference paper
Language
en
Open access
Licence
cc-by
Locations
  • Findings of the Association for Computational Linguistics: ACL (Findings of ACL) (publishedVersion, cc-by)
  • arXiv (Cornell University) (submittedVersion)
  • arXiv (Cornell University)
Funders
  • National Science Foundation (2333740)
  • National Institutes of Health (1R01LM014012)
  • U.S. National Library of Medicine
Topics
  • Physical Sciences › Computer Science › Artificial Intelligence › Topic Modeling
  • Physical Sciences › Computer Science › Information Systems › Information Retrieval and Search Behavior
  • Health Sciences › Medicine › Health Informatics › Artificial Intelligence in Healthcare and Education
Keywords
retrieval-augmented generation, medical question answering, benchmark, hallucinations, large language models, medical corpora, Retriever, chain-of-thought prompting

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