DeLTa: A Decoding Strategy based on Logit Trajectory Prediction Improves Factuality and Reasoning Ability

Yunzhen He, Yusuke Takase, Yoichi Ishibashi, Hidetoshi Shimodaira


Abstract
Large Language Models (LLMs) are increasingly being used in real-world applications. However, concerns about the reliability of the content they generate persist, as it frequently deviates from factual correctness or exhibits deficiencies in logical reasoning. This paper proposes a novel decoding strategy aimed at enhancing both factual accuracy and inferential reasoning without requiring any modifications to the architecture or pre-trained parameters of LLMs. Our approach adjusts next-token probabilities by analyzing the trajectory of logits from lower to higher layers in Transformers and applying linear regression. We find that this Decoding by Logit Trajectory-based approach (DeLTa) effectively reinforces factuality and reasoning while mitigating incorrect generation. Experiments on TruthfulQA demonstrate that DeLTa attains up to a 4.9% improvement over the baseline. Furthermore, it enhances performance by up to 8.1% on StrategyQA and 7.3% on GSM8K, both of which demand strong reasoning capabilities.
Anthology ID:
2025.uncertainlp-main.26
Volume:
Proceedings of the 2nd Workshop on Uncertainty-Aware NLP (UncertaiNLP 2025)
Month:
November
Year:
2025
Address:
Suzhou, China
Editors:
Bryan Eikema, Raúl Vázquez, Jonathan Berant, Marie-Catherine de Marneffe, Barbara Plank, Artem Shelmanov, Swabha Swayamdipta, Jörg Tiedemann, Chrysoula Zerva, Wilker Aziz
Venues:
UncertaiNLP | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
309–321
Language:
URL:
https://preview.aclanthology.org/ingest-dnd/2025.uncertainlp-main.26/
DOI:
10.18653/v1/2025.uncertainlp-main.26
Bibkey:
Cite (ACL):
Yunzhen He, Yusuke Takase, Yoichi Ishibashi, and Hidetoshi Shimodaira. 2025. DeLTa: A Decoding Strategy based on Logit Trajectory Prediction Improves Factuality and Reasoning Ability. In Proceedings of the 2nd Workshop on Uncertainty-Aware NLP (UncertaiNLP 2025), pages 309–321, Suzhou, China. Association for Computational Linguistics.
Cite (Informal):
DeLTa: A Decoding Strategy based on Logit Trajectory Prediction Improves Factuality and Reasoning Ability (He et al., UncertaiNLP 2025)
Copy Citation:
PDF:
https://preview.aclanthology.org/ingest-dnd/2025.uncertainlp-main.26.pdf