Event Detection with a Context-Aware Encoder and LoRA for Improved Performance on Long-Tailed Classes

Abdullah Al Monsur, Nitesh Vamshi Bommisetty, Gene Louis Kim


Abstract
The current state of event detection research has two notable re-occurring limitations that we investigate in this study. First, the unidirectional nature of decoder-only LLMs presents a fundamental architectural bottleneck for natural language understanding tasks that depend on rich, bidirectional context. Second, we confront the conventional reliance on Micro-F1 scores in event detection literature, which systematically inflates performance by favoring majority classes. Instead, we focus on Macro-F1 as a more representative measure of a model’s ability across the long-tail of event types. Our experiments demonstrate that models enhanced with sentence context achieve superior performance over canonical decoder-only baselines. Using Low-Rank Adaptation (LoRA) during finetuning provides a substantial boost in Macro-F1 scores in particular, especially for the decoder-only models, showing that LoRA can be an effective tool to enhance LLMs’ performance on long-tailed event classes.
Anthology ID:
2026.findings-eacl.314
Volume:
Findings of the Association for Computational Linguistics: EACL 2026
Month:
March
Year:
2026
Address:
Rabat, Morocco
Editors:
Vera Demberg, Kentaro Inui, Lluís Marquez
Venue:
Findings
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Publisher:
Association for Computational Linguistics
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Pages:
5985–6003
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URL:
https://preview.aclanthology.org/ingest-eacl/2026.findings-eacl.314/
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Cite (ACL):
Abdullah Al Monsur, Nitesh Vamshi Bommisetty, and Gene Louis Kim. 2026. Event Detection with a Context-Aware Encoder and LoRA for Improved Performance on Long-Tailed Classes. In Findings of the Association for Computational Linguistics: EACL 2026, pages 5985–6003, Rabat, Morocco. Association for Computational Linguistics.
Cite (Informal):
Event Detection with a Context-Aware Encoder and LoRA for Improved Performance on Long-Tailed Classes (Al Monsur et al., Findings 2026)
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