FactUEP at SemEval-2026 Task 4: Structured Narrative Similarity Scoring with Aspect Decomposition and Weak-Signal Gating

Marcin Sawinski


Abstract
This paper presents approach to narrative similarity prediction for SemEval-2026 Task 4 Track A. We introduce an LLM-based system that operationalizes the three core dimensions—Abstract Theme, Course of Action, and Outcomes—via schema-constrained prompting to enforce structured outputs and alignment with the annotation protocol. The system proceeds in three stages: structured aspect decomposition and scoring, weak-signal gating for low-confidence cases, and a targeted LLM-based tiebreak. The final model achieved near-human performance and ranked second on the Track A leaderboard.
Anthology ID:
2026.semeval-1.147
Volume:
Proceedings of the 20th International Workshop on Semantic Evaluation (2026)
Month:
July
Year:
2026
Address:
San Diego, California, USA
Editors:
Ekaterina Kochmar, Debanjan Ghosh, Kai North, Mamoru Komachi
Venues:
SemEval | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1075–1088
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.147/
DOI:
Bibkey:
Cite (ACL):
Marcin Sawinski. 2026. FactUEP at SemEval-2026 Task 4: Structured Narrative Similarity Scoring with Aspect Decomposition and Weak-Signal Gating. In Proceedings of the 20th International Workshop on Semantic Evaluation (2026), pages 1075–1088, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
FactUEP at SemEval-2026 Task 4: Structured Narrative Similarity Scoring with Aspect Decomposition and Weak-Signal Gating (Sawinski, SemEval 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.147.pdf
Supplementarymaterial:
 2026.semeval-1.147.SupplementaryMaterial.zip