Rethinking Stepwise Model Routing: A Cost-Efficient Table Reasoning Perspective

Shenghao Ye, Yuxiang Wang, Yu Guo, Tao Zhang, Shuangwu Chen, Zijian Wen, Qihui Zhu, Mengjie Zhang, Dong Jin, Wang Luo, Jianyang


Abstract
Large Reasoning Models (LRMs) achieve strong performance on table reasoning tasks but incur substantial inference cost due to long reasoning traces. Stepwise model routing mitigates this issue by dynamically assigning reasoning steps to smaller or larger models. However, stepwise model routing for table reasoning remains underexplored. Through empirical analysis, we find that reasoning steps involving tables contain two types of tokens with distinct uncertainty distributions: table tokens grounded in table structure, such as cell values and headers, and text tokens representing surrounding natural-language reasoning. The uncertainty of both token types is correlated with the risk that the model makes an error in the next reasoning step. However, existing methods fail to model them separately, leading to suboptimal routing decisions. To address this, we propose EcoTab, a table-aware stepwise routing framework for efficient table reasoning. For each current reasoning step, EcoTab separately models the two types of tokens and estimates their uncertainties, then combines them to estimate the risk of using the small model for the next step, thereby enabling model selection. Experiments on multiple table reasoning benchmarks show that EcoTab consistently outperforms strong baselines and achieves a better balance between accuracy and efficiency.
Anthology ID:
2026.emnlp-main.1232
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
28102–28120
Language:
URL:
https://aclanthology.org/2026.emnlp-main.1232/
DOI:
Bibkey:
Cite (ACL):
Shenghao Ye, Yuxiang Wang, Yu Guo, Tao Zhang, Shuangwu Chen, Zijian Wen, Qihui Zhu, Mengjie Zhang, Dong Jin, Wang Luo, and Jianyang. 2026. Rethinking Stepwise Model Routing: A Cost-Efficient Table Reasoning Perspective. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 28102–28120, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Rethinking Stepwise Model Routing: A Cost-Efficient Table Reasoning Perspective (Ye et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.1232.pdf