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Main Authors: Li, Zongjie, Wang, Chaozheng, Ma, Pingchuan, Wu, Daoyuan, Wang, Shuai, Gao, Cuiyun, Liu, Yang
Format: Preprint
Published: 2023
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Online Access:https://arxiv.org/abs/2310.01432
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author Li, Zongjie
Wang, Chaozheng
Ma, Pingchuan
Wu, Daoyuan
Wang, Shuai
Gao, Cuiyun
Liu, Yang
author_facet Li, Zongjie
Wang, Chaozheng
Ma, Pingchuan
Wu, Daoyuan
Wang, Shuai
Gao, Cuiyun
Liu, Yang
contents 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.
format Preprint
id arxiv_https___arxiv_org_abs_2310_01432
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Split and Merge: Aligning Position Biases in LLM-based Evaluators
Li, Zongjie
Wang, Chaozheng
Ma, Pingchuan
Wu, Daoyuan
Wang, Shuai
Gao, Cuiyun
Liu, Yang
Computation and Language
Artificial Intelligence
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.
title Split and Merge: Aligning Position Biases in LLM-based Evaluators
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2310.01432