When retrieval outperforms generation: Dense evidence retrieval for scalable fake news detection

Alamgir Munir Qazi, John Philip McCrae, Jamal Nasir


Abstract
The proliferation of misinformation necessitates robust yet computationally efficient fact verification systems. While current state-of-the-art approaches leverage Large Language Models (LLMs) for generating explanatory rationales, these methods face significant computational barriers and hallucination risks in real-world deployments. We present DeReC (Dense Retrieval Classification), a lightweight framework that demonstrates how general-purpose text embeddings can effectively replace autoregressive LLM-based approaches in fact verification tasks. By combining dense retrieval with specialized classification, our system achieves better accuracy while being significantly more efficient. DeReC outperforms explanation-generating LLMs in efficiency, reducing runtime by 95% on RAWFC (23 minutes 36 seconds compared to 454 minutes 12 seconds) and by 92% on LIAR-RAW (134 minutes 14 seconds compared to 1692 minutes 23 seconds), showcasing its effectiveness across varying dataset sizes. On the RAWFC dataset, DeReC achieves an F1 score of 65.58%, surpassing the state-of-the-art method L-Defense (61.20%). Our results demonstrate that carefully engineered retrieval-based systems can match or exceed LLM performance in specialized tasks while being significantly more practical for real-world deployment.
Anthology ID:
2025.ldk-1.26
Volume:
Proceedings of the 5th Conference on Language, Data and Knowledge
Month:
September
Year:
2025
Address:
Naples, Italy
Editors:
Mehwish Alam, Andon Tchechmedjiev, Jorge Gracia, Dagmar Gromann, Maria Pia di Buono, Johanna Monti, Maxim Ionov
Venue:
LDK
SIG:
Publisher:
Unior Press
Note:
Pages:
255–265
Language:
URL:
https://aclanthology.org/2025.ldk-1.26/
DOI:
Bibkey:
Cite (ACL):
Alamgir Munir Qazi, John Philip McCrae, and Jamal Nasir. 2025. When retrieval outperforms generation: Dense evidence retrieval for scalable fake news detection. In Proceedings of the 5th Conference on Language, Data and Knowledge, pages 255–265, Naples, Italy. Unior Press.
Cite (Informal):
When retrieval outperforms generation: Dense evidence retrieval for scalable fake news detection (Qazi et al., LDK 2025)
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PDF:
https://aclanthology.org/2025.ldk-1.26.pdf