Explicit, Implicit, and Scattered: Revisiting Event Extraction to Capture Complex Arguments

Omar Sharif, Joseph Gatto, Madhusudan Basak, Sarah Masud Preum


Abstract
Prior works formulate the extraction of event-specific arguments as a span extraction problem, where event arguments are explicit — i.e. assumed to be contiguous spans of text in a document. In this study, we revisit this definition of Event Extraction (EE) by introducing two key argument types that cannot be modeled by existing EE frameworks. First, implicit arguments are event arguments which are not explicitly mentioned in the text, but can be inferred through context. Second, scattered arguments are event arguments that are composed of information scattered throughout the text. These two argument types are crucial to elicit the full breadth of information required for proper event modeling.To support the extraction of explicit, implicit, and scattered arguments, we develop a novel dataset, DiscourseEE, which includes 7,464 argument annotations from online health discourse. Notably, 51.2% of the arguments are implicit, and 17.4% are scattered, making DiscourseEE a unique corpus for complex event extraction. Additionally, we formulate argument extraction as a text generation problem to facilitate the extraction of complex argument types. We provide a comprehensive evaluation of state-of-the-art models and highlight critical open challenges in generative event extraction. Our data and codebase are available at https://omar-sharif03.github.io/DiscourseEE.
Anthology ID:
2024.emnlp-main.673
Volume:
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Month:
November
Year:
2024
Address:
Miami, Florida, USA
Editors:
Yaser Al-Onaizan, Mohit Bansal, Yun-Nung Chen
Venue:
EMNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
12061–12081
Language:
URL:
https://aclanthology.org/2024.emnlp-main.673
DOI:
10.18653/v1/2024.emnlp-main.673
Bibkey:
Cite (ACL):
Omar Sharif, Joseph Gatto, Madhusudan Basak, and Sarah Masud Preum. 2024. Explicit, Implicit, and Scattered: Revisiting Event Extraction to Capture Complex Arguments. In Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing, pages 12061–12081, Miami, Florida, USA. Association for Computational Linguistics.
Cite (Informal):
Explicit, Implicit, and Scattered: Revisiting Event Extraction to Capture Complex Arguments (Sharif et al., EMNLP 2024)
Copy Citation:
PDF:
https://aclanthology.org/2024.emnlp-main.673.pdf