What Makes a Good Fiqh Retriever? Answer Retrieval for Arabic Islamic Jurisprudence

Somaya Eltanbouly, Heba Sbahi, Samer Rashwani, Abdessalam Bouchekif, Mutaz al-Khatib, Shahd Gaben, Mohammed Ghaly


Abstract
Retrieval-Augmented Generation is used for Islamic question answering, but most systems are evaluated end-to-end, making retrieval failures difficult to isolate from generation failures. We study answer-bearing retrieval for Arabic fiqh, where a passage is relevant only if it states the ruling required by the question. We build a retrieval test collection for Arabic fiqh and use it to evaluate dense, lexical, hybrid, fine-tuned, and madhhab-aware retrieval strategies. The best retriever achieves 0.524 MRR@5, while fine-tuning improves performance to 0.553. Hybrid retrieval provides limited gains for strong models, whereas madhhab-aware filtering more than doubles MRR@5 on school-specific questions. We further present an error analysis showing that the main challenge is distinguishing answer-bearing passages from topically similar passages that do not contain the requested ruling. The best-performing model and fine-tuning dataset are publicly available at https://huggingface.co/collections/somayaeltanbouly/badr-arabic-fiqh-retrieval
Anthology ID:
2026.arabicnlp-main.18
Volume:
Proceedings of The Fourth Arabic Natural Language Processing Conference
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:
247–262
Language:
URL:
https://aclanthology.org/2026.arabicnlp-main.18/
DOI:
Bibkey:
Cite (ACL):
Somaya Eltanbouly, Heba Sbahi, Samer Rashwani, Abdessalam Bouchekif, Mutaz al-Khatib, Shahd Gaben, and Mohammed Ghaly. 2026. What Makes a Good Fiqh Retriever? Answer Retrieval for Arabic Islamic Jurisprudence. In Proceedings of The Fourth Arabic Natural Language Processing Conference, pages 247–262, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
What Makes a Good Fiqh Retriever? Answer Retrieval for Arabic Islamic Jurisprudence (Eltanbouly et al., ArabicNLP 2026)
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PDF:
https://aclanthology.org/2026.arabicnlp-main.18.pdf