journal article·2026-02-02Open access

Deep Reinforcement Learning-Driven Adaptive Prompting for Robust Medical LLM Evaluation

Dong Ding, Wang Xi, Zenghui Ding, Jianqing Gao

Applied Sciences· Volume 16· Issue 3

Abstract

The accurate and reliable evaluation of large language models (LLMs) in medical domains is critical for real-world clinical deployment, automated medical reasoning, and patient safety. However, the evaluation process is highly sensitive to prompt design, and prevalent reliance on fixed or randomly sampled prompt policies often fails to dynamically adapt to clinical context, question complexity, or evolving safety requirements. This article presents a novel reinforcement learning-based framework for multi-prompt selection, which dynamically optimizes prompt policy per input for medical LLM evaluation across the Medical Knowledge Question-Answering dataset (MKQA), the Medical Multiple-Choice Question dataset (MCQ), and the Doctor-Patient Dialogue dataset. We formulate prompt selection as a Markov Decision Process (MDP) and employ a deep Q-Network (DQN) agent to maximize a reward signal incorporating textual accuracy, domain terminology coverage, safety, and dialogue relevance. Experiments on three medical LLM benchmarks demonstrate consistent improvements in composite reward (e.g., a 6.66% increase in MKQA vs. Random Baseline, and a 2.41% increase in Dialogue vs. Fixed Baseline) when compared to baselines. This was accompanied by robust enhancements in Safety (e.g., achieving 1.0000 in MKQA, a 5.26% increase vs. Fixed Baseline; and a 5.03% increase in Dialogue vs. Fixed Baseline) and substantial gains in Medical Terminology Coverage (e.g., a 74.61% increase in MKQA vs. Fixed Baseline, and a 9.13% increase in MCQ vs. Fixed Baseline) when compared to baselines. While varying across tasks, an improvement in accuracy was observed in the MKQA task, and the framework effectively optimizes the multi-objective reward function, even when minor trade-offs in other metrics like Accuracy and Contextual Relevance were observed in some contexts. Our framework enables robust, context-aware, and adaptive evaluation, laying a foundation for safer and more reliable LLM application in healthcare.
Source: crossref · Quality: baseline

Research context

OpenAlex topics: Machine Learning in Healthcare · Topic Modeling · Artificial Intelligence in Healthcare and Education

SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.

Affiliations

School of Data Science, The Chinese University of Hong Kong, Shenzhen, Shenzhen 518172, China

Intelligence Institute of Machine, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China

iFLYTEK Co., Ltd., Hefei 230088, China

Funding

National Key Research and Development Program of China · the Anhui Provincial Major Science and Technology Project · the Anhui Provincial Clinical Medical Research Transformation Project · the Research Funds of Center for Xin'an Medicine and Modernization of Traditional Chinese Medicine of IHM

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