HausaNLP at SemEval-2025 Task 3: Towards a Fine-Grained Model-Aware Hallucination Detection

Maryam Bala, Amina Abubakar, Abdulhamid Abubakar, Abdulkadir Bichi, Hafsa Ahmad, Sani Abdullahi Sani, Idris Abdulmumin, Shamsuddeen Hassan Muhammad, Ibrahim Said Ahmad


Abstract
This paper presents our findings of the Multilingual Shared Task on Hallucinations and Related Observable Overgeneration Mistakes, MU-SHROOM, which focuses on identifying hallucinations and related overgeneration errors in large language models (LLMs). The shared task involves detecting specific text spans that constitute hallucinations in the outputs generated by LLMs in 14 languages. To address this task, we aim to provide a nuanced, model-aware understanding of hallucination occurrences and severity in English. We used natural language inference and fine-tuned a ModernBERT model using a synthetic dataset of 400 samples, achieving an Intersection over Union (IoU) score of 0.032 and a correlation score of 0.422. These results indicate a moderately positive correlation between the model’s confidence scores and the actual presence of hallucinations. The IoU score indicates that our modelhas a relatively low overlap between the predicted hallucination span and the truth annotation. The performance is unsurprising, given the intricate nature of hallucination detection. Hallucinations often manifest subtly, relying on context, making pinpointing their exact boundaries formidable.
Anthology ID:
2025.semeval-1.227
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:
1737–1741
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URL:
https://preview.aclanthology.org/transition-to-people-yaml/2025.semeval-1.227/
DOI:
Bibkey:
Cite (ACL):
Maryam Bala, Amina Abubakar, Abdulhamid Abubakar, Abdulkadir Bichi, Hafsa Ahmad, Sani Abdullahi Sani, Idris Abdulmumin, Shamsuddeen Hassan Muhammad, and Ibrahim Said Ahmad. 2025. HausaNLP at SemEval-2025 Task 3: Towards a Fine-Grained Model-Aware Hallucination Detection. In Proceedings of the 19th International Workshop on Semantic Evaluation (SemEval-2025), pages 1737–1741, Vienna, Austria. Association for Computational Linguistics.
Cite (Informal):
HausaNLP at SemEval-2025 Task 3: Towards a Fine-Grained Model-Aware Hallucination Detection (Bala et al., SemEval 2025)
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https://preview.aclanthology.org/transition-to-people-yaml/2025.semeval-1.227.pdf