PuDy at FadeIT: Enhancing Fine-Grained Fallacy Detection with Hierarchy-Aware Training and Contextual Enrichment
Paper · 2026 · Duy Dang Phu, Son Bui Hong and Dang Van Thin
Summary
The paper presents the top-ranked system in FadeIT's Subtask B, a shared task held at EVALITA 2026. The task is to locate and label fallacious text spans in Italian social media posts, where spans can overlap and labels follow a hierarchical taxonomy. Training data are scarce, and scoring uses Soft F1, which gives partial credit when a prediction matches the parent category of the gold label.
The authors treat the task as multi-label span classification on top of UmBERTo. Each candidate span is represented by its boundary token embeddings plus a width embedding, and the model is trained with Focal Loss.
They add two components:
- Label propagation: whenever a child label is active, its parent label is raised to at least a minimum target value, which matches training to how the metric scores predictions.
- Contextual Enrichment: the Gemini API rewrites only the non-fallacious context and leaves the annotated spans untouched.
The system ranked first with a Soft F1 of 50.92. The results suggest that metric-aware targets and augmentation that keeps the labelled spans intact help in low-resource argument mining.
Key points
- Architecture: UmBERTo encoder; candidate spans are capped at 20 tokens, and each is represented as [h_i; h_j; width embedding] with a sigmoid multi-label classifier.
- Augmentation comparison: a second, "span-relaxed" variant also paraphrases the fallacious spans. It suffered from semantic drift and label noise, so Contextual Enrichment gave steadier precision and the best Soft Micro F1.
- Best run (Run 1): Soft P/R/F1 of 43.76/60.88/50.92, against a baseline Soft F1 of 6.25. Under strict evaluation, however, team TiGRO scored higher (42.13 F1 vs. PuDy's 31.97).
- Failed categories: six fallacy types scored 0.00 F1 in all runs: Causal-oversimplification, Cherry-picking, Circular-reasoning, False-analogy, False-dilemma and Strawman. The authors attribute this to their usually long spans exceeding the 20-token limit.
- Strongest categories: Slogan (up to 64.07 F1) and Name-calling-or-labelling (about 57 F1), both of which tend to be expressed in short spans.
Fields, topics and concepts
📚 Shelves 2The field of science this work belongs to (OpenAlex fields).Computer Science · 16,667 worksArtificial Intelligence · 16,194 works
Cite
Cite as Duy Dang Phu, Son Bui Hong and Dang Van Thin. 2026. PuDy at FadeIT: Enhancing Fine-Grained Fallacy Detection with Hierarchy-Aware Training and Contextual Enrichment. Proceedings of the Ninth Evaluation Campaign of Natural Language Processing and Speech Tools for Italian. Final Workshop (EVALITA 2026).
@inproceedings{phu2026pudy,
title = {{PuDy at FadeIT: Enhancing Fine-Grained Fallacy Detection with Hierarchy-Aware Training and Contextual Enrichment}},
author = {Duy Dang Phu, Son Bui Hong and Dang {Van Thin}},
booktitle = {Proceedings of the Ninth Evaluation Campaign of Natural Language Processing and Speech Tools for Italian. Final Workshop (EVALITA 2026)},
year = {2026},
url = {https://aclanthology.org/2026.evalita-1.65/}
}References
- A. Ramponi, S. Tonelli, FadeIT at EVALITA 2026: Overview of the fallacy detection in italian social media texts task, in: Proceedings of the Ninth Evaluation Campaign of Natural Language Processing and Speech Tools for Italian. Final Workshop (EVALITA 2026), CEUR.org, Bari, Italy, 2026.
- F. Cutugno, A. Miaschi, A. P. Aprosio, G. Rambelli, L. Siciliani, M. A. Stranisci, Evalita 2026: Overview of the 9th evaluation campaign of natural language processing and speech tools for italian, in: Proceedings of the Ninth Evaluation Campaign of Natural Language Processing and Speech Tools for I… find
- Z. Jin, A. Lalwani, T. Vaidhya, X. Shen, Y. Ding, Z. Lyu, M. Sachan, R. Mihalcea, B. Schölkopf, Logical fallacy detection, in: Y. Goldberg, Z. Kozareva, Y. Zhang (Eds.), Findings of the Association for Computational Linguistics: EMNLP 2022, Association for Computational Linguistics, Abu Dhabi, Unite…
- C. Helwe, T. Calamai, P.-H. Paris, C. Clavel, F. Suchanek, MAFALDA: A benchmark and comprehensive study of fallacy detection and classification, in: K. Duh, H. Gomez, S. Bethard (Eds.), Proceedings of the 2024 Conference of the North American Chapter of the Association for Computational Linguistics:… find
- A. Ramponi, A. Daffara, S. Tonelli, Fine-grained fallacy detection with human label variation, in: L. Chiruzzo, A. Ritter, L. Wang (Eds.), Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1… find
- E. Cantín Larumbe, A. Chust Vendrell, Argumentative fallacy detection in political debates, in: E. Chistova, P. Cimiano, S. Haddadan, G. Lapesa, R. Ruiz-Dolz (Eds.), Proceedings of the 12th Argument mining Workshop, Association for Computational Linguistics, Vienna, Austria, 2025, pp. 369–373. URL:… find
- Y. Lei, R. Huang, Boosting logical fallacy reasoning in LLMs via logical structure tree, in: Y. Al-Onaizan, M. Bansal, Y.-N. Chen (Eds.), Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing, Association for Computational Linguistics, Miami, Florida, USA, 2024, pp.… find
- M. Joshi, D. Chen, Y. Liu, D. S. Weld, L. Zettlemoyer, O. Levy, SpanBERT: Improving pre-training by representing and predicting spans, Transactions of the Association for Computational Linguistics 8 (2020) 64–77. URL: https://aclanthology.org/2020.tacl-1.5/. doi: 10.1162/tacl_a_00300 . ↗
- J. Fu, X. Huang, P. Liu, SpanNER: Named entity re-/recognition as span prediction, in: C. Zong, F. Xia, W. Li, R. Navigli (Eds.), Proceedings of the 59th Annual Meeting of the Association for Computational Linguistics and the 11th International Joint Conference on Natural Language Processing (Volume… find
- D. Wadden, U. Wennberg, Y. Luan, H. Hajishirzi, Entity, relation, and event extraction with contextualized span representations, in: K. Inui, J. Jiang, V. Ng, X. Wan (Eds.), Proceedings of the 2019 Conference on Empirical Methods in Natural Language Processing and the 9th International Joint Confere…
- S. Kobayashi, Contextual augmentation: Data augmentation by words with paradigmatic relations, in: M. Walker, H. Ji, A. Stent (Eds.), Proceedings of the 2018 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 2 (Short Papers…
- H. Dai, Z. Liu, W. Liao, X. Huang, Y. Cao, Z. Wu, L. Zhao, S. Xu, F. Zeng, W. Liu, N. Liu, S. Li, D. Zhu, H. Cai, L. Sun, Q. Li, D. Shen, T. Liu, X. Li, AugGPT: Leveraging ChatGPT for Text Data Augmentation , IEEE Transactions on Big Data 11 (2025) 907–918. URL: https://doi.ieeecomputersociety. org/… — [doi:10.1109/tbdata.2025.3536934](https://doi.org/10.1109/tbdata.2025.3536934) ↗
- D. Kaushik, E. Hovy, Z. C. Lipton, Learning the difference that makes a difference with counterfactually augmented data, International Conference on Learning Representations (ICLR) (2020). find
- L. Parisi, S. Francia, P. Magnani, Umberto: an italian language model trained with whole word masking, https://github.com/musixmatchresearch/umberto, 2020. ↗
- T.-Y. Lin, P. Goyal, R. Girshick, K. He, P. Dollár, Focal loss for dense object detection, in: 2017 IEEE International Conference on Computer Vision (ICCV), 2017, pp. 2999–3007. doi: 10.1109/ICCV. 2017.324 .
- J. Cegin, B. Pecher, J. Simko, I. Srba, M. Bielikova, P. Brusilovsky, Use random selection for now: Investigation of few-shot selection strategies in LLM-based text augmentation, in: C. Christodoulopoulos, T. Chakraborty, C. Rose, V. Peng (Eds.), Findings of the Association for Computational Linguis… find
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