@inproceedings{chandler-etal-2025-deloitte,
title = "Deloitte (Drocks) at {S}em{E}val-2025 Task 3: Fine-Grained Multi-lingual Hallucination Detection Using Internal {LLM} Weights",
author = "Chandler, Alex and
Abburi, Harika and
Bhattacharya, Sanmitra and
Bowen, Edward and
Pudota, Nirmala",
editor = "Rosenthal, Sara and
Ros{\'a}, Aiala and
Ghosh, Debanjan and
Zampieri, Marcos",
booktitle = "Proceedings of the 19th International Workshop on Semantic Evaluation (SemEval-2025)",
month = jul,
year = "2025",
address = "Vienna, Austria",
publisher = "Association for Computational Linguistics",
url = "https://aclanthology.org/2025.semeval-1.144/",
pages = "1089--1097",
ISBN = "979-8-89176-273-2",
abstract = "Large Language Models (LLMs) have greatly advanced the field of Natural Language Generation (NLG). Despite their remarkable capabilities, their tendency to hallucinate{---}producing inaccurate or misleading information-remains a barrier to wider adoption. Current hallucination detection methods mainly employ coarse-grained binary classification at the sentence or document level, overlooking the need for precise identification of the specific text spans containing hallucinations. In this paper, we proposed a methodology that generates supplementary context and processes text using an LLM to extract internal weights (features) from various layers. These extracted features serve as input for a neural network classifier designed to perform token-level binary detection of hallucinations. Subsequently, we map the resulting token-level predictions to character-level predictions, enabling the identification of spans of hallucinated text, which we refer to as hallucination spans. Our model achieved a top-ten ranking in 13 of the 14 languages and secured first place for the French language in the SemEval: Multilingual Shared-task on Hallucinations and Related Observable Overgeneration Mistakes (Mu-SHROOM), utilizing the Mu-SHROOM dataset provided by the task organizers."
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<abstract>Large Language Models (LLMs) have greatly advanced the field of Natural Language Generation (NLG). Despite their remarkable capabilities, their tendency to hallucinate—producing inaccurate or misleading information-remains a barrier to wider adoption. Current hallucination detection methods mainly employ coarse-grained binary classification at the sentence or document level, overlooking the need for precise identification of the specific text spans containing hallucinations. In this paper, we proposed a methodology that generates supplementary context and processes text using an LLM to extract internal weights (features) from various layers. These extracted features serve as input for a neural network classifier designed to perform token-level binary detection of hallucinations. Subsequently, we map the resulting token-level predictions to character-level predictions, enabling the identification of spans of hallucinated text, which we refer to as hallucination spans. Our model achieved a top-ten ranking in 13 of the 14 languages and secured first place for the French language in the SemEval: Multilingual Shared-task on Hallucinations and Related Observable Overgeneration Mistakes (Mu-SHROOM), utilizing the Mu-SHROOM dataset provided by the task organizers.</abstract>
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%0 Conference Proceedings
%T Deloitte (Drocks) at SemEval-2025 Task 3: Fine-Grained Multi-lingual Hallucination Detection Using Internal LLM Weights
%A Chandler, Alex
%A Abburi, Harika
%A Bhattacharya, Sanmitra
%A Bowen, Edward
%A Pudota, Nirmala
%Y Rosenthal, Sara
%Y Rosá, Aiala
%Y Ghosh, Debanjan
%Y Zampieri, Marcos
%S Proceedings of the 19th International Workshop on Semantic Evaluation (SemEval-2025)
%D 2025
%8 July
%I Association for Computational Linguistics
%C Vienna, Austria
%@ 979-8-89176-273-2
%F chandler-etal-2025-deloitte
%X Large Language Models (LLMs) have greatly advanced the field of Natural Language Generation (NLG). Despite their remarkable capabilities, their tendency to hallucinate—producing inaccurate or misleading information-remains a barrier to wider adoption. Current hallucination detection methods mainly employ coarse-grained binary classification at the sentence or document level, overlooking the need for precise identification of the specific text spans containing hallucinations. In this paper, we proposed a methodology that generates supplementary context and processes text using an LLM to extract internal weights (features) from various layers. These extracted features serve as input for a neural network classifier designed to perform token-level binary detection of hallucinations. Subsequently, we map the resulting token-level predictions to character-level predictions, enabling the identification of spans of hallucinated text, which we refer to as hallucination spans. Our model achieved a top-ten ranking in 13 of the 14 languages and secured first place for the French language in the SemEval: Multilingual Shared-task on Hallucinations and Related Observable Overgeneration Mistakes (Mu-SHROOM), utilizing the Mu-SHROOM dataset provided by the task organizers.
%U https://aclanthology.org/2025.semeval-1.144/
%P 1089-1097
Markdown (Informal)
[Deloitte (Drocks) at SemEval-2025 Task 3: Fine-Grained Multi-lingual Hallucination Detection Using Internal LLM Weights](https://aclanthology.org/2025.semeval-1.144/) (Chandler et al., SemEval 2025)
ACL