How Reliable Are LLM Annotators for Online Manipulation? Evidence from Phishing and Abuse Corpora

Senaid Popovic, Damien Riquet, Maxime Meyer, Fabien Lauer, Yannick Parmentier


Abstract
In this paper, we evaluate an LLM-assisted process for annotating persuasion intent in the context of online manipulation. We focus on the DIDECO taxonomy, a two-tier framework of explicit and implicit manipulation categories based on Speech Act Theory and Cialdini’s influence principles. Our question is not whether such annotations support a downstream classifier, but whether they are reliable enough to be used as labels in the first place. We measure reliability as Cohen’s $\kappa$ between a model and human gold labels, and between models, evaluating GPT-4o, Claude Sonnet 4.5, and Llama 3.3-70B on a synthetic corpus. On DIDECO, models agree more with one another than with human gold, suggesting shared annotation heuristics that diverge from human judgement. On an unlabeled real-world corpus, hierarchical prompting increases inter-model agreement for two of three model pairs, but this result establishes consistency rather than correctness. On a separate human-annotated real-world corpus, we evaluate Claude Sonnet 4.5, Gemma 3-27B, and Qwen 2.5-7B at both top-level and sub-label resolution. Claude and Gemma exceed human agreement at the top level, whereas Claude is the only model to exceed held-out human benchmarks across the full 23-label taxonomy; Gemma also does so when sparse sub-labels are excluded. These results tend to show that LLM annotation reliability depends on the corpus and label granularity, and that inter-model agreement cannot substitute for human validation. We release the prompts, code, and sub-label definitions.
Anthology ID:
2026.woah-1.26
Volume:
Proceedings of the 10th Workshop on Online Abuse and Harms (WOAH)
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Agostina Calabrese, Thomas Davidson, Christine de Kock, Urja Khurana, Marta Marchiori Manerba, Paloma Piot, Zeerak Talat
Venues:
WOAH | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
298–306
Language:
URL:
https://aclanthology.org/2026.woah-1.26/
DOI:
Bibkey:
Cite (ACL):
Senaid Popovic, Damien Riquet, Maxime Meyer, Fabien Lauer, and Yannick Parmentier. 2026. How Reliable Are LLM Annotators for Online Manipulation? Evidence from Phishing and Abuse Corpora. In Proceedings of the 10th Workshop on Online Abuse and Harms (WOAH), pages 298–306, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
How Reliable Are LLM Annotators for Online Manipulation? Evidence from Phishing and Abuse Corpora (Popovic et al., WOAH 2026)
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PDF:
https://aclanthology.org/2026.woah-1.26.pdf
Supplementarymaterial:
 2026.woah-1.26.SupplementaryMaterial.zip