@inproceedings{penteado-mcgillivray-2026-annotating,
title = "Annotating Extremist Severity in {B}razilian {P}ortuguese: Human{--}{LLM} Divergence Across Labels, Evidence, and Interpretation",
author = "Penteado, Ricardo and
McGillivray, Barbara",
editor = "Calabrese, Agostina and
Davidson, Thomas and
de Kock, Christine and
Khurana, Urja and
Marchiori Manerba, Marta and
Piot, Paloma and
Talat, Zeerak",
booktitle = "Proceedings of the 10th Workshop on Online Abuse and Harms ({WOAH})",
month = oct,
year = "2026",
address = "Budapest, Hungary",
publisher = "Association for Computational Linguistics",
url = "https://aclanthology.org/2026.woah-1.25/",
pages = "284--297",
ISBN = "979-8-89176-487-3",
abstract = "This study examines how large language models annotate implicit extremist discourse in Brazilian Portuguese, and where their decisions diverge from human judgement. Using 1,843 risk-enriched segments, we compare three trained human annotators with GPT-4o, Gemini 2.5 Pro, and Claude 4 Sonnet under the same schema-constrained protocol. Each annotation includes a three-level severity label, an extractive evidence span, discourse-pragmatic metadata, and confidence, while human disagreements are adjudicated to produce a single adjudicated reference. We evaluate models against the adjudicated reference using accuracy, macro-F1, and Cohen{'}s {\ensuremath{\kappa}}, complement this with a multi-reference evaluation that preserves individual human variation, and additionally examine evidence-span overlap and whether shared evidence leads to the same severity judgement. LLMs agree with one another more than humans do, yet align only moderately with the adjudicated reference. They provide longer and cleaner evidence spans, but overlap with human rationales does not predict label correctness. Errors concentrate in the implicit class, where models often recognise similar cues but assign different severity levels. These findings identify agreement, confidence, and rationale overlap as unreliable proxies for annotation validity, and motivate evidence- and interpretation-level diagnostics for harmful-content annotation."
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<abstract>This study examines how large language models annotate implicit extremist discourse in Brazilian Portuguese, and where their decisions diverge from human judgement. Using 1,843 risk-enriched segments, we compare three trained human annotators with GPT-4o, Gemini 2.5 Pro, and Claude 4 Sonnet under the same schema-constrained protocol. Each annotation includes a three-level severity label, an extractive evidence span, discourse-pragmatic metadata, and confidence, while human disagreements are adjudicated to produce a single adjudicated reference. We evaluate models against the adjudicated reference using accuracy, macro-F1, and Cohen’s \ensuremathąppa, complement this with a multi-reference evaluation that preserves individual human variation, and additionally examine evidence-span overlap and whether shared evidence leads to the same severity judgement. LLMs agree with one another more than humans do, yet align only moderately with the adjudicated reference. They provide longer and cleaner evidence spans, but overlap with human rationales does not predict label correctness. Errors concentrate in the implicit class, where models often recognise similar cues but assign different severity levels. These findings identify agreement, confidence, and rationale overlap as unreliable proxies for annotation validity, and motivate evidence- and interpretation-level diagnostics for harmful-content annotation.</abstract>
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%0 Conference Proceedings
%T Annotating Extremist Severity in Brazilian Portuguese: Human–LLM Divergence Across Labels, Evidence, and Interpretation
%A Penteado, Ricardo
%A McGillivray, Barbara
%Y Calabrese, Agostina
%Y Davidson, Thomas
%Y de Kock, Christine
%Y Khurana, Urja
%Y Marchiori Manerba, Marta
%Y Piot, Paloma
%Y Talat, Zeerak
%S Proceedings of the 10th Workshop on Online Abuse and Harms (WOAH)
%D 2026
%8 October
%I Association for Computational Linguistics
%C Budapest, Hungary
%@ 979-8-89176-487-3
%F penteado-mcgillivray-2026-annotating
%X This study examines how large language models annotate implicit extremist discourse in Brazilian Portuguese, and where their decisions diverge from human judgement. Using 1,843 risk-enriched segments, we compare three trained human annotators with GPT-4o, Gemini 2.5 Pro, and Claude 4 Sonnet under the same schema-constrained protocol. Each annotation includes a three-level severity label, an extractive evidence span, discourse-pragmatic metadata, and confidence, while human disagreements are adjudicated to produce a single adjudicated reference. We evaluate models against the adjudicated reference using accuracy, macro-F1, and Cohen’s \ensuremathąppa, complement this with a multi-reference evaluation that preserves individual human variation, and additionally examine evidence-span overlap and whether shared evidence leads to the same severity judgement. LLMs agree with one another more than humans do, yet align only moderately with the adjudicated reference. They provide longer and cleaner evidence spans, but overlap with human rationales does not predict label correctness. Errors concentrate in the implicit class, where models often recognise similar cues but assign different severity levels. These findings identify agreement, confidence, and rationale overlap as unreliable proxies for annotation validity, and motivate evidence- and interpretation-level diagnostics for harmful-content annotation.
%U https://aclanthology.org/2026.woah-1.25/
%P 284-297
Markdown (Informal)
[Annotating Extremist Severity in Brazilian Portuguese: Human–LLM Divergence Across Labels, Evidence, and Interpretation](https://aclanthology.org/2026.woah-1.25/) (Penteado & McGillivray, WOAH 2026)
ACL