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arXiv 2603.21172cs.CL
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仅凭熵不足以在LLMs中实现安全的选择性预测

Entropy Alone is Insufficient for Safe Selective Prediction in LLMs

Department of Engineering Science, University of Oxford(牛津大学工程科学系);Oxford Suzhou Centre for Advanced Research, University of Oxford(牛津大学苏州市先进研究中心)

Edward Phillips, Fredrik K. Gustafsson, Sean Wu, Anshul Thakur, David A. Clifton

AI总结:

本文探讨了熵基于不确定性方法在选择性预测中的不足,提出结合熵分数与正确性探测信号的方法,提升风险-覆盖权衡和校准性能。

摘要:

选择性预测系统可通过避免高风险情况来缓解语言模型幻觉带来的危害。不确定性量化技术常用于识别此类情况,但在更广泛的选择性预测策略和低目标误差率操作能力方面的评估较少。我们发现熵基不确定性方法存在模型依赖性失效模式,导致不可靠的回避行为,并通过结合熵分数与正确性探测信号加以解决。在三个QA基准(TriviaQA、BioASQ、MedicalQA)和四个模型家族中,综合分数通常能改善风险-覆盖权衡和校准性能,相较于仅依赖熵的基线。我们的结果强调了对不确定性方法的部署面向评估的重要性,使用直接反映系统能否在规定风险水平下运行的指标。

英文摘要:

Selective prediction systems can mitigate harms resulting from language model hallucinations by abstaining from answering in high-risk cases. Uncertainty quantification techniques are often employed to identify such cases, but are rarely evaluated in the context of the wider selective prediction policy and its ability to operate at low target error rates. We identify a model-dependent failure mode of entropy-based uncertainty methods that leads to unreliable abstention behaviour, and address it by combining entropy scores with a correctness probe signal. We find that across three QA benchmarks (TriviaQA, BioASQ, MedicalQA) and four model families, the combined score generally improves both the risk--coverage trade-off and calibration performance relative to entropy-only baselines. Our results highlight the importance of deployment-facing evaluation of uncertainty methods, using metrics that directly reflect whether a system can be trusted to operate at a stated risk level.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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