rabia_naz at StanceEval-2026: An Ensemble of Fine-Tuned Open LLMs for Arabic Stance Detection on Seen Targets

Rabia Naz


Abstract
This paper presents a system for StanceEval-2026 Track 1, Arabic stance detection on seen targets. Systems in this track are trained on the provided targets and evaluated on a related target within the same thematic domain. Open large language models are fine-tuned with QLoRA on the original Mawqif training data and adapted to the test target through transductive self-training, in which unlabeled test tweets are added to training only when independent models agree on their label. The final prediction is a majority vote over three fine-tuned models, Qwen2.5-7B, the Arabic-native ALLaM-7B, and a sarcasm-aware variant that predicts the official sarcasm label before the stance label. The system scored 0.7564 Favg2 and placed 12th of 21 teams on the official leaderboard. Across seventeen scored variants, task fine-tuning outperformed zero-shot prompting at every model scale, heterogeneous fine-tuned models converged on 98% of test predictions, and further gains required decorrelated ensemble members. The sarcasm annotation supplied this decorrelation and improved the vote, while the sentiment annotation degraded it.
Anthology ID:
2026.arabicnlp-sharedtasks.70
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:
538–543
Language:
URL:
https://aclanthology.org/2026.arabicnlp-sharedtasks.70/
DOI:
Bibkey:
Cite (ACL):
Rabia Naz. 2026. rabia_naz at StanceEval-2026: An Ensemble of Fine-Tuned Open LLMs for Arabic Stance Detection on Seen Targets. In Proceedings of The Fourth Arabic Natural Language Processing Conference: Shared Tasks, pages 538–543, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
rabia_naz at StanceEval-2026: An Ensemble of Fine-Tuned Open LLMs for Arabic Stance Detection on Seen Targets (Naz, ArabicNLP 2026)
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PDF:
https://aclanthology.org/2026.arabicnlp-sharedtasks.70.pdf