ChulaNLP at SemEval-2026 Task 6: A Hybrid BERT-LLM Framework for Political Response Clarity and Evasion Detection
Paper · 2026 · Wisarut Peerachaidecho and Attapol Rutherford
Summary
The paper addresses SemEval-2026 Task 6 (CLARITY). The task asks systems to tell whether politicians' interview responses actually answer the question. Subtask 1 labels each response with a three-way clarity level. Subtask 2 identifies one of nine evasion techniques.
The authors work with English question–answer pairs from White House presidential interview transcripts. A large share of these pairs exceeds the 512-token limit of standard encoders. They compare fine-tuned encoders (DeBERTa, RooseBERT and BigBird) and find that DeBERTa-large, trained on truncated rather than discarded long inputs, works best. Its five most probable labels are then given to an LLM (Kimi-K2, prompted few-shot) as a restricted choice set. The LLM's evasion label is mapped back to a clarity level for Subtask 1.
This combination outperforms either component alone. It ranked 7th in Subtask 1 and 2nd in Subtask 2 of the final evaluation. The work shows that cheap, task-tuned encoders can usefully narrow the decision space for general-purpose LLMs in fine-grained pragmatic classification.
Key points
- Data cleaning: Of 3,448 training pairs, duplicate annotations with conflicting labels were removed, leaving 3,364 instances. The development set has 308 pairs. About 36.6% of training pairs and 43.5% of development pairs exceed 512 tokens.
- Encoder comparison: Truncated DeBERTa-large was the strongest encoder on the development set, with Subtask 2 macro F1 of 0.46 and top-5 accuracy of 0.97. BigBird-RoBERTa-base and RooseBERT-base-cased lagged behind.
- Hybrid on the development set: Few-shot Kimi-K2 restricted to the top-5 candidates reached macro F1 of 0.52 on Subtask 2. Using all nine labels, Kimi-K2 and DeepSeek scored roughly 0.39–0.45.
- Hybrid on the official test set: The system scored 0.82 on Subtask 1 and 0.61 on Subtask 2. The organizers' fine-tuned LLM baseline scored 0.82 and 0.57 respectively.
- Per-class difficulty: Explicit answers were easiest to detect (F1 0.63). Deflection (0.22), Implicit (0.26) and General (0.33) were hardest, which the authors attribute to their subtle pragmatic cues.
Institutions
Fields, topics and concepts
📚 Shelves 6The field of science this work belongs to (OpenAlex fields).Computer Science · 16,667 worksArtificial Intelligence · 16,194 worksArts and Humanities · 16,039 worksLanguage and Linguistics · 15,891 worksSocial Sciences · 1,772 worksGeneral Social Sciences · 227 works
Cite
Cite as Wisarut Peerachaidecho and Attapol Rutherford. 2026. ChulaNLP at SemEval-2026 Task 6: A Hybrid BERT-LLM Framework for Political Response Clarity and Evasion Detection. Proceedings of the 20th International Workshop on Semantic Evaluation (2026).
@inproceedings{peerachaidecho2026chulanlp,
title = {{ChulaNLP at SemEval-2026 Task 6: A Hybrid BERT-LLM Framework for Political Response Clarity and Evasion Detection}},
author = {Wisarut Peerachaidecho and Attapol Rutherford},
booktitle = {Proceedings of the 20th International Workshop on Semantic Evaluation (2026)},
year = {2026},
doi = {10.18653/v1/2026.semeval-1.236},
url = {https://doi.org/10.18653/v1/2026.semeval-1.236}
}References
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