Representation-based Broad Hallucination Detectors Fail to Generalize Out of Distribution

Zuzanna Dubanowska, Maciej Żelaszczyk, Michał Brzozowski, Paolo Mandica, Michal P. Karpowicz


Abstract
We critically assess the efficacy of the current SOTA in hallucination detection and find that its performance on the RAGTruth dataset is largely driven by a spurious correlation with data. Controlling for this effect, state-of-the-art performs no better than supervised linear probes, while requiring extensive hyperparameter tuning across datasets. Out-of-distribution generalization is currently out of reach, with all of the analyzed methods performing close to random. We propose a set of guidelines for hallucination detection and its evaluation.
Anthology ID:
2025.findings-emnlp.952
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2025
Month:
November
Year:
2025
Address:
Suzhou, China
Editors:
Christos Christodoulopoulos, Tanmoy Chakraborty, Carolyn Rose, Violet Peng
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
17563–17575
Language:
URL:
https://preview.aclanthology.org/author-page-yu-wang-polytechnic/2025.findings-emnlp.952/
DOI:
10.18653/v1/2025.findings-emnlp.952
Bibkey:
Cite (ACL):
Zuzanna Dubanowska, Maciej Żelaszczyk, Michał Brzozowski, Paolo Mandica, and Michal P. Karpowicz. 2025. Representation-based Broad Hallucination Detectors Fail to Generalize Out of Distribution. In Findings of the Association for Computational Linguistics: EMNLP 2025, pages 17563–17575, Suzhou, China. Association for Computational Linguistics.
Cite (Informal):
Representation-based Broad Hallucination Detectors Fail to Generalize Out of Distribution (Dubanowska et al., Findings 2025)
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https://preview.aclanthology.org/author-page-yu-wang-polytechnic/2025.findings-emnlp.952.pdf
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