HarmMetric Eval: Benchmarking Metrics and Judges for LLM Harmfulness Assessment

Fuente: arXiv
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Main Authors: Yang, Langqi, Zheng, Tianhang, Chen, Yixuan, Xiu, Kedong, Zhou, Hao, Ni, Wangze, Chen, Lei, Qin, Zhan, Ren, Kui
Format: Preprint
Published: 2025
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author Yang, Langqi
Zheng, Tianhang
Chen, Yixuan
Xiu, Kedong
Zhou, Hao
Ni, Wangze
Chen, Lei
Qin, Zhan
Ren, Kui
author_facet Yang, Langqi
Zheng, Tianhang
Chen, Yixuan
Xiu, Kedong
Zhou, Hao
Ni, Wangze
Chen, Lei
Qin, Zhan
Ren, Kui
contents The potential of large language models (LLMs) to generate harmful content poses a significant safety risk for data management, as LLMs are increasingly being used as engines for data generation. To assess this risk, numerous harmfulness evaluation metrics and judges have been proposed. However, due to differences in their formats and scales, these metrics may yield inconsistent evaluation results on LLM-generated harmful data, undermining their credibility in practice. To address this gap, we present HarmMetric Eval, a systematic benchmark for assessing the quality of harmfulness metrics and judges with varying formats and scales. HarmMetric Eval includes a high-quality dataset comprising representative harmful prompts paired with harmful and non-harmful LLM outputs across multiple fine-grained categories, along with a unified scoring mechanism to reward the metrics for correctly ranking harmful outputs over non-harmful ones. Extensive experiments on HarmMetric Eval yield a surprising finding: conventional reference-based metrics such as ROUGE and METEOR can outperform LLM-based judges in fine-grained harmfulness evaluation, challenging prevailing assumptions about LLMs' superiority in this domain. To reveal the reasons behind this finding, we provide a fine-grained analysis to explain the limitations of LLM-based judges on rating irrelevant or useless LLM outputs. Motivated by these insights, we design an improved harmfulness judge that explicitly incorporates fine-grained harmfulness criteria in its prompt template and leverages reference-based metrics for lightweight fine-tuning of its base LLM. The resulting judge achieves state-of-the-art evaluation effectiveness on HarmMetric Eval.
format Preprint
id arxiv_https___arxiv_org_abs_2509_24384
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle HarmMetric Eval: Benchmarking Metrics and Judges for LLM Harmfulness Assessment
Yang, Langqi
Zheng, Tianhang
Chen, Yixuan
Xiu, Kedong
Zhou, Hao
Ni, Wangze
Chen, Lei
Qin, Zhan
Ren, Kui
Computation and Language
Artificial Intelligence
The potential of large language models (LLMs) to generate harmful content poses a significant safety risk for data management, as LLMs are increasingly being used as engines for data generation. To assess this risk, numerous harmfulness evaluation metrics and judges have been proposed. However, due to differences in their formats and scales, these metrics may yield inconsistent evaluation results on LLM-generated harmful data, undermining their credibility in practice. To address this gap, we present HarmMetric Eval, a systematic benchmark for assessing the quality of harmfulness metrics and judges with varying formats and scales. HarmMetric Eval includes a high-quality dataset comprising representative harmful prompts paired with harmful and non-harmful LLM outputs across multiple fine-grained categories, along with a unified scoring mechanism to reward the metrics for correctly ranking harmful outputs over non-harmful ones. Extensive experiments on HarmMetric Eval yield a surprising finding: conventional reference-based metrics such as ROUGE and METEOR can outperform LLM-based judges in fine-grained harmfulness evaluation, challenging prevailing assumptions about LLMs' superiority in this domain. To reveal the reasons behind this finding, we provide a fine-grained analysis to explain the limitations of LLM-based judges on rating irrelevant or useless LLM outputs. Motivated by these insights, we design an improved harmfulness judge that explicitly incorporates fine-grained harmfulness criteria in its prompt template and leverages reference-based metrics for lightweight fine-tuning of its base LLM. The resulting judge achieves state-of-the-art evaluation effectiveness on HarmMetric Eval.
title HarmMetric Eval: Benchmarking Metrics and Judges for LLM Harmfulness Assessment
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2509.24384