LLMs for Argument Mining: Detection, Extraction, and Relationship Classification of pre-defined Arguments in Online Comments

Matteo Guida, Yulia Otmakhova, Eduard Hovy, Lea Frermann


Abstract
Automated large-scale analysis of public discussions around contested issues like abortion requires detecting and understanding the use of arguments. While Large Language Models (LLMs) have shown promise in language processing tasks, their performance in mining topic-specific, pre-defined arguments in online comments remains underexplored. We evaluate four state-of-the-art LLMs on three argument mining tasks using datasets comprising over 2,000 opinion comments across six polarizing topics. Quantitative evaluation suggests an overall strong performance across the three tasks, especially for large and fine-tuned LLMs, albeit at a significant environmental cost. However, a detailed error analysis revealed systematic shortcomings on long and nuanced comments and emotionally charged language, raising concerns for downstream applications like content moderation or opinion analysis. Our results highlight both the promise and current limitations of LLMs for automated argument analysis in online comments.
Anthology ID:
2025.alta-main.12
Volume:
Proceedings of The 23rd Annual Workshop of the Australasian Language Technology Association
Month:
November
Year:
2025
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Sydney, Australia
Editors:
Jonathan K. Kummerfeld, Aditya Joshi, Mark Dras
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ALTA
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Publisher:
Association for Computational Linguistics
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Pages:
176–191
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URL:
https://preview.aclanthology.org/ingest-alta/2025.alta-main.12/
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Cite (ACL):
Matteo Guida, Yulia Otmakhova, Eduard Hovy, and Lea Frermann. 2025. LLMs for Argument Mining: Detection, Extraction, and Relationship Classification of pre-defined Arguments in Online Comments. In Proceedings of The 23rd Annual Workshop of the Australasian Language Technology Association, pages 176–191, Sydney, Australia. Association for Computational Linguistics.
Cite (Informal):
LLMs for Argument Mining: Detection, Extraction, and Relationship Classification of pre-defined Arguments in Online Comments (Guida et al., ALTA 2025)
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https://preview.aclanthology.org/ingest-alta/2025.alta-main.12.pdf