JLShen at StanceEval-2026: Cross-Lab LLM Ensembles and a Break-Even Rule for the Excluded Class

Junlong Shen


Abstract
Our two systems for StanceEval-2026, Arabic stance detection on Mawqif-XT, placed 1st of 31 on Track 1 (Favg2 = 0.8994) and 2nd of 22 on Track 2 (0.9357). Track 1 averages six zero shot readings of each tweet by frontier models from two providers, and calls a fine-tuned Arabic pipeline only to break exact ties. Track 2 is one reader, given a short generated description of the target so it can score stance expressed through a related topic. The leaderboard publishes three aggregate scores over the same predictions, and reading them shows that about 60% of our errors on both tracks are tweets annotated NONE that we placed in a stance class. Because the score ignores that class, the gain from moving such a row is fixed before the row is read. We derive the precision a repair must reach, and nine rankings plus an oracle from the corpus’s own annotation columns all fall short of it.
Anthology ID:
2026.arabicnlp-sharedtasks.71
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:
544–551
Language:
URL:
https://aclanthology.org/2026.arabicnlp-sharedtasks.71/
DOI:
Bibkey:
Cite (ACL):
Junlong Shen. 2026. JLShen at StanceEval-2026: Cross-Lab LLM Ensembles and a Break-Even Rule for the Excluded Class. In Proceedings of The Fourth Arabic Natural Language Processing Conference: Shared Tasks, pages 544–551, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
JLShen at StanceEval-2026: Cross-Lab LLM Ensembles and a Break-Even Rule for the Excluded Class (Shen, ArabicNLP 2026)
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PDF:
https://aclanthology.org/2026.arabicnlp-sharedtasks.71.pdf