Large Language Models are Inconsistent and Biased Evaluators

Fuente: arXiv
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Autori principali: Stureborg, Rickard, Alikaniotis, Dimitris, Suhara, Yoshi
Natura: Preprint
Pubblicazione: 2024
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author Stureborg, Rickard
Alikaniotis, Dimitris
Suhara, Yoshi
author_facet Stureborg, Rickard
Alikaniotis, Dimitris
Suhara, Yoshi
contents The zero-shot capability of Large Language Models (LLMs) has enabled highly flexible, reference-free metrics for various tasks, making LLM evaluators common tools in NLP. However, the robustness of these LLM evaluators remains relatively understudied; existing work mainly pursued optimal performance in terms of correlating LLM scores with human expert scores. In this paper, we conduct a series of analyses using the SummEval dataset and confirm that LLMs are biased evaluators as they: (1) exhibit familiarity bias-a preference for text with lower perplexity, (2) show skewed and biased distributions of ratings, and (3) experience anchoring effects for multi-attribute judgments. We also found that LLMs are inconsistent evaluators, showing low "inter-sample" agreement and sensitivity to prompt differences that are insignificant to human understanding of text quality. Furthermore, we share recipes for configuring LLM evaluators to mitigate these limitations. Experimental results on the RoSE dataset demonstrate improvements over the state-of-the-art LLM evaluators.
format Preprint
id arxiv_https___arxiv_org_abs_2405_01724
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Large Language Models are Inconsistent and Biased Evaluators
Stureborg, Rickard
Alikaniotis, Dimitris
Suhara, Yoshi
Computation and Language
Artificial Intelligence
68T50 (Primary) 68T01, 68T37, 91F20 (Secondary)
I.2; I.2.7; I.7
The zero-shot capability of Large Language Models (LLMs) has enabled highly flexible, reference-free metrics for various tasks, making LLM evaluators common tools in NLP. However, the robustness of these LLM evaluators remains relatively understudied; existing work mainly pursued optimal performance in terms of correlating LLM scores with human expert scores. In this paper, we conduct a series of analyses using the SummEval dataset and confirm that LLMs are biased evaluators as they: (1) exhibit familiarity bias-a preference for text with lower perplexity, (2) show skewed and biased distributions of ratings, and (3) experience anchoring effects for multi-attribute judgments. We also found that LLMs are inconsistent evaluators, showing low "inter-sample" agreement and sensitivity to prompt differences that are insignificant to human understanding of text quality. Furthermore, we share recipes for configuring LLM evaluators to mitigate these limitations. Experimental results on the RoSE dataset demonstrate improvements over the state-of-the-art LLM evaluators.
title Large Language Models are Inconsistent and Biased Evaluators
topic Computation and Language
Artificial Intelligence
68T50 (Primary) 68T01, 68T37, 91F20 (Secondary)
I.2; I.2.7; I.7
url https://arxiv.org/abs/2405.01724