Take It All: Ensemble Retrieval for Multimodal Evidence Aggregation

Max Upravitelev, Veronika Solopova, Premtim Sahitaj, Ariana Sahitaj, Charlott Jakob, Sebastian Möller, Vera Schmitt


Abstract
Multimodal fact checking has become increasingly important due to the predominance of visual content on social media platforms, where images are frequently used to enhance the credibility and spread of misleading claims, while generated images become more prevalent and realistic as generative models advance. Incorporating visual information, however, substantially increases computational costs, raising critical efficiency concerns for practical deployment. In this study, we propose and evaluate the ADA-AGGR (ensemble retrievAl for multimoDAl evidence AGGRegation) pipeline, which achieved the second place on both the dev and test leaderboards of the FEVER 9/AVerImaTeC shared task. However, long runtimes per claim highlight challenges regarding efficiency concerns when designing multimodal claim verification pipelines. We therefore run extensive ablation studies and configuration analyses to identify possible performance–runtime improvements. Our experiments show that substantial efficiency gains are possible without significant loss in verification quality. For instance, we reduced the average runtime by up to 6.28× while maintaining comparable performance across evaluation metrics by aggressively downsampling input images processed by visual language models. Overall, our results highlight that careful design choices are crucial for building scalable and resource-efficient multimodal fact-checking systems suitable for real-world deployment.
Anthology ID:
2026.fever-1.7
Volume:
Proceedings of the Ninth Fact Extraction and VERification Workshop (FEVER)
Month:
March
Year:
2026
Address:
Rabat, Morocco
Editors:
Mubashara Akhtar, Rami Aly, Rui Cao, Christos Christodoulopoulos, Oana Cocarascu, Zhijiang Guo, Arpit Mittal, Michael Schlichtkrull, James Thorne, Andreas Vlachos
Venues:
FEVER | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
91–107
Language:
URL:
https://aclanthology.org/2026.fever-1.7/
DOI:
Bibkey:
Cite (ACL):
Max Upravitelev, Veronika Solopova, Premtim Sahitaj, Ariana Sahitaj, Charlott Jakob, Sebastian Möller, and Vera Schmitt. 2026. Take It All: Ensemble Retrieval for Multimodal Evidence Aggregation. In Proceedings of the Ninth Fact Extraction and VERification Workshop (FEVER), pages 91–107, Rabat, Morocco. Association for Computational Linguistics.
Cite (Informal):
Take It All: Ensemble Retrieval for Multimodal Evidence Aggregation (Upravitelev et al., FEVER 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.fever-1.7.pdf