NYUAD at QIAS Shared Task: Benchmarking the Legal Reasoning of LLMs in Arabic Islamic Inheritance Cases
Paper · 2025 · Nouar AlDahoul and Yasir Zaki
Summary
The paper asks how well current large language models handle Islamic inheritance law (ʿIlm al-Mawārīth). This rule-heavy domain requires identifying the rightful heirs and computing their fractional shares, and doing it by hand is slow and error-prone. The authors use the QIAS 2025 shared-task data: Arabic multiple-choice questions drawn from expert-checked IslamWeb fatwas, with three difficulty tiers. They compare four groups of systems:
- open Arabic models (Falcon3, Fanar, Allam, ALLaM-Thinking);
- proprietary models used through their APIs (Gemini Flash/Pro 2.5, GPT-4o, GPT o3);
- the same models under a plain prompt and a zero-shot chain-of-thought prompt;
- supervised fine-tunes of Llama 4 Scout (LoRA), GPT-4o and Gemini Flash.
The open Arabic models score well under 40%, while the frontier reasoning models exceed 90% on validation. Fine-tuning helps GPT-4o but hurts Gemini. The final submission takes a majority vote over three strong base models and reaches 92.7% test accuracy, which placed third in the challenge. The study shows where LLMs stand on structured legal-arithmetic reasoning in Arabic.
Key points
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Data. QIAS 2025 has six options (A–F) per question and beginner, intermediate and advanced levels. It is sourced from about 32,000 fatwas and split 9,446 / 1,000 / 1,000 into train, validation and test.
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Base models on validation:
Model Accuracy Falcon3 24.2% Fanar 31.7% Allam 38.8% ALLaM-Thinking 29.2% GPT-4o 70.1% Gemini Flash 2.5 91.5% GPT o3 92.3% -
Prompt sensitivity. Switching to the step-by-step prompt lifts GPT-4o from 57.5% to 70.1%. Gemini Flash 2.5 barely changes (90.7% vs 91.5%).
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Fine-tuning:
- GPT-4o rises to 84.7% without a system prompt and 86.6% with the CoT system prompt.
- Llama 4 Scout (LoRA, 4-bit, 7 epochs) reaches 84.3% / 82.4%.
- Gemini Flash 2.5 falls to 74.6%, and Flash 2 (adapter size 8) reaches only 64.6%.
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Test set. Single models score o3 88.4%, Flash 2.5 88.1% and Pro 2.5 87.9%. A majority vote of the three gives 92.7%. The Llama fine-tunes are published as NYUAD_Llama4_Inheritance_Solver (two versions).
Interesting ideas
- I1. A plain majority vote over three near-equal strong models gained about four points over the best single model, so their errors were largely uncorrelated.
- I2. Fine-tuning a reasoning-optimized model on bare answer labels appeared to erode its step-by-step behaviour, and the authors suggest supervision needs the rationale, not just the final letter.
- I3. Running every model under two prompt formats exposed which models really understand the task and which depend on prompt wording.
- I4. The authors admit that a sub-point gap between two models from a single run is not meaningful and plan to report mean and variance over repeated runs.
- I5. Inheritance questions combine identifying who exists in a family with exact fraction arithmetic over those people, which is structured world reasoning rather than text matching.
For Mova
How these ideas could serve Mova, our small open language model — its files, stages and tests:
- I1 (learn): Silver trees could be accepted only where several witness parsers agree, with disagreements routed to an LLM teacher tier instead of being averaged away.
- I2 (learn): When an LLM teacher labels data, it should store the justification chain together with the label, so trained components keep an explainable path.
- I3 (learn): Evaluation could rephrase each test item in several surface forms and flag a component whose accuracy swings, as a robustness check next to negative controls.
- I4 (learn): Parser or reader comparisons should report spread over several seeds or runs before declaring a winner.
- I5 (answer): Such cases would make a good stress test for maths word-problem readers that must build entities and relations before computing shares.
Institutions
Fields, topics and concepts
📚 Shelves 6The field of science this work belongs to (OpenAlex fields).Computer Science · 16,667 worksArtificial Intelligence · 16,194 worksArts and Humanities · 16,039 worksLanguage and Linguistics · 15,891 worksSocial Sciences · 1,772 worksPolitical Science and International Relations · 182 works
🧭 Topics 3Research subjects and languages the work is about.Reasoning · 1,426 worksSemitic languages · 2,908 worksLegal AI · 134 works
Cite
Cite as Nouar AlDahoul and Yasir Zaki. 2025. NYUAD at QIAS Shared Task: Benchmarking the Legal Reasoning of LLMs in Arabic Islamic Inheritance Cases. Proceedings of The Third Arabic Natural Language Processing Conference: Shared Tasks.
@inproceedings{aldahoul2025nyuad,
title = {{NYUAD at QIAS Shared Task: Benchmarking the Legal Reasoning of LLMs in Arabic Islamic Inheritance Cases}},
author = {Nouar AlDahoul and Yasir Zaki},
booktitle = {Proceedings of The Third Arabic Natural Language Processing Conference: Shared Tasks},
year = {2025},
doi = {10.18653/v1/2025.arabicnlp-sharedtasks.118},
url = {https://doi.org/10.18653/v1/2025.arabicnlp-sharedtasks.118}
}References
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