Axiom at StanceEval-2026: A Two-Stage Hybrid Cascade for Arabic Stance Detection

Md. Ajwad Hossain


Abstract
Cross-target Arabic stance detection presents a unique challenge due to the rich morphological complexity, regional dialects, and heavy reliance on sarcasm within social media discourse. In this paper, we describe the system submitted by Team Axiom for Track 1 (Seen Targets) of the StanceEval-2026 shared task. Our primary contribution is a resource-efficient, Two-Stage Hybrid Cascade architecture. This system utilizes a fine-tuned MARBERTv2 encoder as a high-confidence gatekeeper, dynamically routing uncertain and complex tweets to a locally hosted, 4-bit quantized Large Language Model (Llama-3.1-8B-Instruct). To prevent label bias and ground the LLM’s reasoning, the fallback stage incorporates a dynamically balanced, class-specific TF-IDF sub-word retriever. Our official submission achieved an Favg2 score of 0.6910 (Rank 18), demonstrating a measurable improvement over our standalone encoder baseline (0.6722).
Anthology ID:
2026.arabicnlp-sharedtasks.68
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:
524–528
Language:
URL:
https://aclanthology.org/2026.arabicnlp-sharedtasks.68/
DOI:
Bibkey:
Cite (ACL):
Md. Ajwad Hossain. 2026. Axiom at StanceEval-2026: A Two-Stage Hybrid Cascade for Arabic Stance Detection. In Proceedings of The Fourth Arabic Natural Language Processing Conference: Shared Tasks, pages 524–528, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Axiom at StanceEval-2026: A Two-Stage Hybrid Cascade for Arabic Stance Detection (Hossain, ArabicNLP 2026)
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PDF:
https://aclanthology.org/2026.arabicnlp-sharedtasks.68.pdf