Auto-Arena: Automating LLM Evaluations with Agent Peer Battles and Committee Discussions
Paper · 2025 · Ruochen Zhao, Wenxuan Zhang, Yew Ken Chia et al.
Summary
Keeping up with rapidly released LLMs requires evaluation that is both fast and trustworthy. Static benchmarks such as MMLU or MT-Bench risk contamination and handle open-ended output poorly. Crowdsourced platforms like Chatbot Arena are trusted but need many human votes, which makes them slow for new models and weak for non-English use. Auto-Arena replaces every human role with LLM agents in three stages. First, an examiner model writes fresh questions across eight conversation categories. Next, two candidate models hold a three-round debate modelled on the Lincoln-Douglas format: they answer, critique each other, and pose follow-up challenges. Finally, a panel of judge models discusses the transcript and votes on a winner. Across 15 recent LLMs, the resulting ranking reached 92.14% Spearman correlation with human preferences, which the authors report as better than prior expert-built benchmarks, with no manual effort. The approach matters because it yields timely, adaptable leaderboards that could extend to other domains and languages.
Key points
- Debate actions: candidates can use four actions: THINK (a hidden plan), RESPOND, CRITICIZE and RAISE (follow-up questions).
- Bias controls:
- Speaking order is randomized to counter positional bias.
- Both sides get equal turns.
- A length cap truncates long answers to curb verbosity bias.
- The examiner is not told it will compete in the tournament.
- Judging committee: the five top-ranked models serve as judges, excluding the debaters and models from their families. The initial ranking is seeded from MMLU scores.
- Observed behaviours: candidates target their opponents' weak spots. They also adopt good habits from each other; for example, Claude-3-Haiku picked up Command R+'s roleplay speech style.
- Code and limitations: the code is released at github.com/DAMO-NLP-SG/Auto-Arena-LLMs. The authors list three limitations: the question-domain distribution is hand-designed, the framework only supports 1-vs-1 battles, and judges inherit LLM-as-a-judge biases.
Institutions
Fields, topics and concepts
📚 Shelves 5The field of science this work belongs to (OpenAlex fields).Computer Science · 16,667 worksArtificial Intelligence · 16,194 worksArts and Humanities · 16,039 worksLanguage and Linguistics · 15,891 worksInformation Systems · 1,437 works
Cite
Cite as Ruochen Zhao, Wenxuan Zhang, Yew Ken Chia, Weiwen Xu, Deli Zhao and Lidong Bing. 2025. Auto-Arena: Automating LLM Evaluations with Agent Peer Battles and Committee Discussions. Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers).
@inproceedings{zhao2025auto,
title = {{Auto-Arena: Automating LLM Evaluations with Agent Peer Battles and Committee Discussions}},
author = {Ruochen Zhao, Wenxuan Zhang, Yew Ken Chia, Weiwen Xu, Deli Zhao and Lidong Bing},
booktitle = {Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)},
year = {2025},
doi = {10.18653/v1/2025.acl-long.223},
url = {https://doi.org/10.18653/v1/2025.acl-long.223}
}References
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