FiRC-NLP at SemEval-2025 Task 3: Exploring Prompting Approaches for Detecting Hallucinations in LLMs

Wondimagegnhue Tufa, Fadi Hassan, Guillem Collell, Dandan Tu, Yi Tu, Sang Ni, Kuan Eeik Tan


Abstract
This paper presents a system description forthe SemEval Mu-SHROOM task, focusing ondetecting hallucination spans in the outputsof instruction-tuned Large Language Models(LLMs) across 14 languages. We comparetwo distinct approaches: Prompt-Based Ap-proach (PBA), which leverages the capabilityof LLMs to detect hallucination spans usingdifferent prompting strategies, and the Fine-Tuning-Based Approach (FBA), which fine-tunes pre-trained Language Models (LMs) toextract hallucination spans in a supervised man-ner. Our experiments reveal that PBA, espe-cially when incorporating explicit references orexternal knowledge, outperforms FBA. How-ever, the effectiveness of PBA varies across lan-guages, likely due to differences in languagerepresentation within LLMs
Anthology ID:
2025.semeval-1.273
Volume:
Proceedings of the 19th International Workshop on Semantic Evaluation (SemEval-2025)
Month:
July
Year:
2025
Address:
Vienna, Austria
Editors:
Sara Rosenthal, Aiala Rosá, Debanjan Ghosh, Marcos Zampieri
Venues:
SemEval | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
2096–2102
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URL:
https://preview.aclanthology.org/transition-to-people-yaml/2025.semeval-1.273/
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Cite (ACL):
Wondimagegnhue Tufa, Fadi Hassan, Guillem Collell, Dandan Tu, Yi Tu, Sang Ni, and Kuan Eeik Tan. 2025. FiRC-NLP at SemEval-2025 Task 3: Exploring Prompting Approaches for Detecting Hallucinations in LLMs. In Proceedings of the 19th International Workshop on Semantic Evaluation (SemEval-2025), pages 2096–2102, Vienna, Austria. Association for Computational Linguistics.
Cite (Informal):
FiRC-NLP at SemEval-2025 Task 3: Exploring Prompting Approaches for Detecting Hallucinations in LLMs (Tufa et al., SemEval 2025)
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https://preview.aclanthology.org/transition-to-people-yaml/2025.semeval-1.273.pdf