HelsinkiTeam at HalluScoring-2026: Domain-Adaptive Arabic Hallucination Detection and Answer Selection with ALLaM

Yazid Bounab, Azeddine Benlamoudi, Wassim Swaileh, Mia Sivén


Abstract
The rapid advancement of large language models (LLMs) has enabled powerful AI applications, yet hallucinations remain a major challenge to their reliability. As part of Track 2 of the HalluScoring 2026 shared task at ArabicNLP 2026, we present a system for detecting hallucinated answers and selecting the correct answer from six closely related candidates. We adapt the Arabic–English ALLaM-7B-Instruct model using Low-Rank Adaptation (LoRA) with domain-specific supervision from Qur’anic text, Hadith, Islamic law and inheritance, Islamic history, and general knowledge. The system jointly performs hallucination detection and answer selection, achieving 88.9% accuracy and 88.6% macro-F1 for hallucination detection, and 91.1% answer selection accuracy on the 800-instance development set. Error analysis identifies geography and structured-output parsing as the main remaining weaknesses.
Anthology ID:
2026.arabicnlp-sharedtasks.145
Volume:
Proceedings of The Fourth Arabic Natural Language Processing Conference: Shared Tasks
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Muhammad Abdul-Mageed, Tamer Elsayed, Houda Bouamor, Samhaa El-Beltagy, Hend Al-Khalifa, Ahmed Abdelali, AbdelRahim Elmadany, Abdellah El Mekki, Kareem Darwish, Sakhar Alkhereyf, Hamzah Luqman, Salam Khalifa, Samar Magdy, Zaid Alyafeai, Injy Hamed, Wajdi Zaghouani, Imed Zitouni
Venue:
ArabicNLP
SIG:
SIGARAB
Publisher:
Association for Computational Linguistics
Note:
Pages:
1165–1170
Language:
URL:
https://aclanthology.org/2026.arabicnlp-sharedtasks.145/
DOI:
Bibkey:
Cite (ACL):
Yazid Bounab, Azeddine Benlamoudi, Wassim Swaileh, and Mia Sivén. 2026. HelsinkiTeam at HalluScoring-2026: Domain-Adaptive Arabic Hallucination Detection and Answer Selection with ALLaM. In Proceedings of The Fourth Arabic Natural Language Processing Conference: Shared Tasks, pages 1165–1170, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
HelsinkiTeam at HalluScoring-2026: Domain-Adaptive Arabic Hallucination Detection and Answer Selection with ALLaM (Bounab et al., ArabicNLP 2026)
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PDF:
https://aclanthology.org/2026.arabicnlp-sharedtasks.145.pdf