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arXiv 2310.01432cs.CLcs.AI
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拆分与合并:校准基于大语言模型的评估器中的位置偏差

Split and Merge: Aligning Position Biases in LLM-based Evaluators

Hong Kong University of Science and Technology(香港科技大学);Harbin Institute of Technology(哈尔滨工业大学);Nanyang Technological University(南洋理工大学)

Zongjie Li, Chaozheng Wang, Pingchuan Ma, Daoyuan Wu, Shuai Wang, Cuiyun Gao, Yang Liu

AI总结:

针对基于大语言模型的评估器存在的位置偏差问题,提出轻量对齐系统PORTIA,通过拆分、对齐、合并答案片段校准偏差,显著提升评估一致性与成本效益。

摘要:

大语言模型(LLM)作为自动化评估器用于评估AI系统生成答案的质量已展现出应用前景。然而,这类基于LLM的评估器在成对比较候选答案时会表现出位置偏差(即不一致性),无论答案内容如何,都会偏向第一个或第二个答案。为解决这一局限,我们提出PORTIA——一种基于对齐的系统,旨在模拟人类的比较策略,以轻量且有效的方式校准位置偏差。具体而言,PORTIA将答案拆分为多个片段,对齐不同候选答案中的相似内容,再将其合并回单个提示中供LLM评估。我们使用6种不同的LLM开展了大量实验,共评估11520个答案对。结果表明,PORTIA显著提升了所有测试模型和比较形式下的一致性率,平均相对提升幅度达47.46%。值得注意的是,PORTIA让性能稍弱的GPT模型仅以10%的成本就能达到与当前最优的GPT-4模型88%的一致率。此外,它修正了GPT-4模型中约80%的位置偏差实例,将其一致性率提升至98%。后续的人工评估显示,经PORTIA增强的GPT-3.5模型在与人类评估者的对齐度上甚至能超过独立的GPT-4。这些结果凸显了PORTIA在修正位置偏差、提升LLM一致性并兼顾成本效益的同时增强性能的能力,为在各类应用中更可靠、可扩展地使用LLM开展自动化评估迈出了有价值的一步。

英文摘要:

Large language models (LLMs) have shown promise as automated evaluators for assessing the quality of answers generated by AI systems. However, these LLM-based evaluators exhibit position bias, or inconsistency, when used to evaluate candidate answers in pairwise comparisons, favoring either the first or second answer regardless of content. To address this limitation, we propose PORTIA, an alignment-based system designed to mimic human comparison strategies to calibrate position bias in a lightweight yet effective manner. Specifically, PORTIA splits the answers into multiple segments, aligns similar content across candidate answers, and then merges them back into a single prompt for evaluation by LLMs. We conducted extensive experiments with six diverse LLMs to evaluate 11,520 answer pairs. Our results show that PORTIA markedly enhances the consistency rates for all the models and comparison forms tested, achieving an average relative improvement of 47.46%. Remarkably, PORTIA enables less advanced GPT models to achieve 88% agreement with the state-of-the-art GPT-4 model at just 10% of the cost. Furthermore, it rectifies around 80% of the position bias instances within the GPT-4 model, elevating its consistency rate up to 98%. Subsequent human evaluations indicate that the PORTIA-enhanced GPT-3.5 model can even surpass the standalone GPT-4 in terms of alignment with human evaluators. These findings highlight PORTIA's ability to correct position bias, improve LLM consistency, and boost performance while keeping cost-efficiency. This represents a valuable step toward a more reliable and scalable use of LLMs for automated evaluations across diverse applications.

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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