M3EC: A Multimodal Multidocument Benchmark for Event Extraction and Event Coreference Resolution

Zaber Ibn Abdul Hakim, Najibul Haque Sarker, Aafiya Hussain, Hani Alomari, Alvi Md Ishmam, Ali Asgarov, Chia-Wei Tang, Chris Thomas


Abstract
Understanding how the same real-world event is represented across text, video, and audio remains a fundamental challenge in information extraction. While prior datasets have explored events within individual modalities or limited modality pairs, a setting that combines all three modalities remains largely unexplored. We introduce M3EC (Multimodal Multidocument Event Coreference), a new benchmark for multimodal, multidocument event extraction and coreference resolution. It is built from tightly related news clusters that combine eventful videos, audio files, and news articles. We also introduce a semi-automated annotation pipeline, AutoEventAnnotator, to generate automated annotations at scale. Additionally, we construct a human-annotated test set for robust evaluation. To our knowledge, this is the first benchmark to support cluster-level multidocument event extraction and event coreference across text, video, and audio. Evaluation with strong multimodal LLMs shows that the majority of them fail to extract valid events in video and particularly in audio. We further show that models finetuned on the annotations generated by our automated pipeline achieve consistent improvements, including more than +30 F1 on video event extraction, +15 F1 on audio event extraction, and +40 CoNLL F1 on end-to-end coreference resolution, highlighting the usefulness of M3EC for training and evaluation in multimodal event understanding.
Anthology ID:
2026.emnlp-main.2502
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
56843–56904
Language:
URL:
https://aclanthology.org/2026.emnlp-main.2502/
DOI:
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Cite (ACL):
Zaber Ibn Abdul Hakim, Najibul Haque Sarker, Aafiya Hussain, Hani Alomari, Alvi Md Ishmam, Ali Asgarov, Chia-Wei Tang, and Chris Thomas. 2026. M3EC: A Multimodal Multidocument Benchmark for Event Extraction and Event Coreference Resolution. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 56843–56904, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
M3EC: A Multimodal Multidocument Benchmark for Event Extraction and Event Coreference Resolution (Abdul Hakim et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.2502.pdf