Chronos: Learning Temporal Dynamics of Reasoning Chains for Test-Time Scaling

Kai Zhang, Jiayi Liao, Chengpeng Li, Ziyuan Xie, Sihang Li, Xiang Wang


Abstract
Test-Time Scaling (TTS) has emerged as an effective paradigm for improving the reasoning performance of large language models (LLMs). However, existing methods — most notably majority voting and heuristic token-level scoring — treat reasoning traces or tokens equally, thereby being susceptible to substantial variations in trajectory quality and localized logical failures. In this work, we introduce **Chronos**, a lightweight and plug-and-play chronological reasoning scorer that models each trajectory as a time series. Specifically, Chronos learns to capture trajectory features of token probabilities, assigns quality scores accordingly, and employs a weighted voting mechanism. Extensive evaluations on both in-domain and out-of-domain benchmarks demonstrate that Chronos consistently delivers substantial gains across a variety of models, with negligible computational overhead. Notably, Chronos@128 achieves relative improvements of 34.21% over Pass@1 and 22.70% over Maj@128 on HMMT25 using Qwen3-4B-Thinking-2507, highlighting its effectiveness.
Anthology ID:
2026.findings-acl.1376
Volume:
Findings of the Association for Computational Linguistics: ACL 2026
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
Findings
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Publisher:
Association for Computational Linguistics
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Pages:
27651–27664
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URL:
https://preview.aclanthology.org/ingest-acl/2026.findings-acl.1376/
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Cite (ACL):
Kai Zhang, Jiayi Liao, Chengpeng Li, Ziyuan Xie, Sihang Li, and Xiang Wang. 2026. Chronos: Learning Temporal Dynamics of Reasoning Chains for Test-Time Scaling. In Findings of the Association for Computational Linguistics: ACL 2026, pages 27651–27664, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Chronos: Learning Temporal Dynamics of Reasoning Chains for Test-Time Scaling (Zhang et al., Findings 2026)
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https://preview.aclanthology.org/ingest-acl/2026.findings-acl.1376.pdf
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