Can LLMs Evaluate What They Cannot Annotate? Revisiting LLM Reliability in Hate Speech Detection

Paloma Piot, David Otero, Patricia Martin-Rodilla, Javier Parapar


Abstract
Hate speech spreads widely online and harms both individuals and communities, making automatic detection essential for large-scale moderation. However, accurately detecting hate speech remains a difficult task. Part of the challenge lies in subjectivity: what one person flags as hate speech, another may see as benign. Traditional annotation agreement metrics, such as Cohen’s k, oversimplify this disagreement, treating it as an error rather than meaningful diversity. Meanwhile, Large Language Models (LLMs) promise scalable annotation, but prior studies demonstrate that they cannot fully replace human judgement, especially in subjective tasks. In this work, we reexamine LLM reliability using a subjectivity-aware framework, cross-Replication Reliability (xRR), revealing that even under fairer lens, LLMs still diverge from humans. Yet this limitation opens an opportunity: we find that LLM-generated annotations can reliably reflect performance trends across classification models, correlating with human evaluations. We test this by examining whether LLM-generated annotations preserve the relative ordering of model performance derived from human evaluation (i.e. whether models ranked as more reliable by human annotators preserve the same order when evaluated with LLM-generated labels). Our results show that, although LLMs differ from humans at the instance level, they reproduce similar ranking and classification patterns, suggesting their potential as proxy evaluators. While not a substitute for human annotators, they might serve as a scalable proxy for evaluation in subjective NLP tasks.
Anthology ID:
2026.lrec-1.341
Volume:
Proceedings of the Fifteenth Language Resources and Evaluation Conference
Month:
May
Year:
2026
Address:
Palma de Mallorca, Spain
Editors:
Stelios Piperidis, Núria Bel, Henk van den Heuvel, Nancy Ide, Simon Krek, Antonio Toral
Venue:
LREC
SIG:
Publisher:
ELRA Language Resource Association
Note:
Pages:
4358–4370
Language:
External URL:
https://lrec.elra.info/lrec2026-main-341
DOI:
10.63317/22n5hekovvrz
Bibkey:
Cite (ACL):
Paloma Piot, David Otero, Patricia Martin-Rodilla, and Javier Parapar. 2026. Can LLMs Evaluate What They Cannot Annotate? Revisiting LLM Reliability in Hate Speech Detection. In Proceedings of the Fifteenth Language Resources and Evaluation Conference, pages 4358–4370, Palma de Mallorca, Spain. ELRA Language Resource Association.
Cite (Informal):
Can LLMs Evaluate What They Cannot Annotate? Revisiting LLM Reliability in Hate Speech Detection (Piot et al., LREC 2026)
Copy Citation: