MisSynth: Improving MISSCI Logical Fallacies Classification with
  Synthetic Data
Authors: name: Mykhailo Poliakov; name: Nadiya Shvai
Published: 2025-10-30 10:52:43

Abstract: Health-related misinformation is very prevalent and potentially harmful. It
is difficult to identify, especially when claims distort or misinterpret
scientific findings. We investigate the impact of synthetic data generation and
lightweight fine-tuning techniques on the ability of large language models
(LLMs) to recognize fallacious arguments using the MISSCI dataset and
framework. In this work, we propose MisSynth, a pipeline that applies
retrieval-augmented generation (RAG) to produce synthetic fallacy samples,
which are then used to fine-tune an LLM model. Our results show substantial
accuracy gains with fine-tuned models compared to vanilla baselines. For
instance, the LLaMA 3.1 8B fine-tuned model achieved an over 35% F1-score
absolute improvement on the MISSCI test split over its vanilla baseline. We
demonstrate that introducing synthetic fallacy data to augment limited
annotated resources can significantly enhance zero-shot LLM classification
performance on real-world scientific misinformation tasks, even with limited
computational resources. The code and synthetic dataset are available on
https://github.com/mxpoliakov/MisSynth.