Abstract
Typed decision models such as Jev offer an efficient alternative to generative LLMs in decision-making workflows by selecting directly from predefined options. When candidate sets contain no valid answer, TypeSafe recommends including an "other" or "none-of-the-above" option to enable rejection. In this report, however, we identify an arithmetic-dependent rejection bottleneck: Jev reliably selects correct numerical answers when available but frequently accepts incorrect alternatives when they are absent despite an explicit rejection option. On paired arithmetic problems, answer-present accuracy reaches 99%, while correct rejection falls to 7%. Moreover, this gap persists across numerical magnitudes, operation depths, contextual formulations, and rejection labels, and extends to scenarios such as time calculation and capacity rounding. Yet native Boolean verification achieves 99% exact-match accuracy on the same answer-absent arithmetic cases, showing that categorical rejection can fail even when the model successfully verifies candidate correctness. Finally, we show that a simple decision threshold selected on separate development problems raises arithmetic rejection accuracy from 7% to 79% while retaining 97% answer-present accuracy, substantially mitigating the failure without retraining or additional inference.
Keywords
Subject
Publication details
- Journal
- Not available
- Open access
- Green open access
Cite this article
APA 7
Zhong, J., Li, M., & Lai, Y. (2026). When the Right Answer Is Missing: An Arithmetic-Dependent Rejection Bottleneck in Jev. https://omanscience.com/en/articles/when-the-right-answer-is-missing-an-arithmetic-dependent-rejection-bottleneck-in-jev
MLA 9
Zhong, Jike, et al. "When the Right Answer Is Missing: An Arithmetic-Dependent Rejection Bottleneck in Jev." https://omanscience.com/en/articles/when-the-right-answer-is-missing-an-arithmetic-dependent-rejection-bottleneck-in-jev.
Chicago (author–date)
Zhong, Jike, Ming Li, and Yuxiang Lai. 2026. "When the Right Answer Is Missing: An Arithmetic-Dependent Rejection Bottleneck in Jev." https://omanscience.com/en/articles/when-the-right-answer-is-missing-an-arithmetic-dependent-rejection-bottleneck-in-jev.
Harvard
Zhong, J., Li, M. and Lai, Y. (2026) 'When the Right Answer Is Missing: An Arithmetic-Dependent Rejection Bottleneck in Jev', Available at: https://omanscience.com/en/articles/when-the-right-answer-is-missing-an-arithmetic-dependent-rejection-bottleneck-in-jev.
Vancouver
Zhong J, Li M, Lai Y. When the Right Answer Is Missing: An Arithmetic-Dependent Rejection Bottleneck in Jev. https://omanscience.com/en/articles/when-the-right-answer-is-missing-an-arithmetic-dependent-rejection-bottleneck-in-jev
IEEE
J. Zhong, M. Li, and Y. Lai, "When the Right Answer Is Missing: An Arithmetic-Dependent Rejection Bottleneck in Jev," https://omanscience.com/en/articles/when-the-right-answer-is-missing-an-arithmetic-dependent-rejection-bottleneck-in-jev.