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arXiv 2408.01935cs.CLcs.AI
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定义与评估应用于自然语言推理的语言模型中的决策风险与复合风险

Defining and Evaluating Decision and Composite Risk in Language Models Applied to Natural Language Inference

University of Southern California(南加州大学);Information Sciences Institute(信息科学研究所)

Ke Shen, Mayank Kejriwal

AI总结:

针对语言模型信心不足风险研究缺失的问题,本文定义决策风险与复合风险,并提出含弃权决策的两级推理评估框架,在四个常识推理数据集上验证其可更准确区分高低风险任务。

摘要:

尽管大型语言模型(LLM)表现出色,但众所周知,ChatGPT等模型存在重要风险。其中一类风险源于模型对其推理持有的错误置信度,无论是过度自信还是信心不足。前者已得到充分研究,后者却没有,这导致在基于错误置信度理解模型综合风险方面存在不对称性。本文通过定义两类风险(决策风险和复合风险)来解决这种不对称性,并提出一个实验框架,该框架由两级推理架构以及用于在判别式和生成式LLM中衡量此类风险的适当指标组成。第一级依赖于一条决策规则,用于确定底层语言模型是否应当对推理弃权(不执行)。第二级(在模型未弃权时适用)是模型的推理。我们在四个自然语言常识推理数据集上,使用一个基于集成的开源RoBERTa模型和ChatGPT开展了详细实验,证明了该评估框架的实用价值。例如,结果表明,我们的框架能够使LLM对额外20.1%的低风险推理任务自信作答,而其他方法可能将这些任务误判为高风险;同时跳过19.8%原本会被错误回答的高风险任务。

英文摘要:

Despite their impressive performance, large language models (LLMs) such as ChatGPT are known to pose important risks. One such set of risks arises from misplaced confidence, whether over-confidence or under-confidence, that the models have in their inference. While the former is well studied, the latter is not, leading to an asymmetry in understanding the comprehensive risk of the model based on misplaced confidence. In this paper, we address this asymmetry by defining two types of risk (decision and composite risk), and proposing an experimental framework consisting of a two-level inference architecture and appropriate metrics for measuring such risks in both discriminative and generative LLMs. The first level relies on a decision rule that determines whether the underlying language model should abstain from inference. The second level (which applies if the model does not abstain) is the model's inference. Detailed experiments on four natural language commonsense reasoning datasets using both an open-source ensemble-based RoBERTa model and ChatGPT, demonstrate the practical utility of the evaluation framework. For example, our results show that our framework can get an LLM to confidently respond to an extra 20.1% of low-risk inference tasks that other methods might misclassify as high-risk, and skip 19.8% of high-risk tasks, which would have been answered incorrectly.

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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