Beyond Timestamps: Bridging Forward and Backward Reasoning in Temporal Numerical and Relational Understanding

Xinying Qian, Ying Zhang, Xuhui Sui, Yu Zhao, Baohang Zhou, Jeff Z. Pan


Abstract
Temporal reasoning remains a critical challenge for large language models (LLMs), particularly when it requires encompassing relational dependencies and numerical constraints. Yet, existing benchmarks largely overlook the joint consideration of these two dimensions and primarily rely on single-task evaluation paradigms, making it difficult to assess whether correct answers reflect grounded reasoning or arise from superficial statistical recall. To address these gaps, we introduce TNR, a benchmark designed to evaluate both Temporal Numerical and Relational reasoning. We propose a bi-directional evaluation framework consisting of forward generation via Question Answering (QA) and backward verification via Fact Verification (FV). By measuring the alignment between QA and FV, we introduce a Consistency Rate to quantify the robustness of reasoning across these two directions. Experiments on a range of LLMs reveal notable discrepancies between QA and FV performance, particularly in numerical and interval-based tasks. Moreover, our bi-directional error analysis demonstrates that these inconsistencies often stem from heuristic shortcuts and statistical co-occurrences rather than grounded logical deduction, flaws that are frequently masked in standard single-task evaluations.
Anthology ID:
2026.acl-long.331
Volume:
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
7301–7321
Language:
URL:
https://preview.aclanthology.org/ingest-acl/2026.acl-long.331/
DOI:
Bibkey:
Cite (ACL):
Xinying Qian, Ying Zhang, Xuhui Sui, Yu Zhao, Baohang Zhou, and Jeff Z. Pan. 2026. Beyond Timestamps: Bridging Forward and Backward Reasoning in Temporal Numerical and Relational Understanding. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 7301–7321, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Beyond Timestamps: Bridging Forward and Backward Reasoning in Temporal Numerical and Relational Understanding (Qian et al., ACL 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl/2026.acl-long.331.pdf
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 2026.acl-long.331.checklist.pdf