Is That Your Final Answer? Test-Time Scaling Improves Selective Question Answering

William Jurayj, Jeffrey Cheng, Benjamin Van Durme


Abstract
Scaling the test-time compute of large language models has demonstrated impressive performance on reasoning benchmarks. However, existing evaluations of test-time scaling make the strong assumption that a reasoning system should always give an answer to any question provided. This overlooks concerns about whether a model is confident in its answer, and whether it is appropriate to always provide a response. To address these concerns, we extract confidence scores during reasoning for thresholding model responses. We find that increasing compute budget at inference time not only helps models answer more questions correctly, but also increases confidence in correct responses. We then extend the current paradigm of zero-risk responses during evaluation by considering settings with non-zero levels of response risk, and suggest a recipe for reporting evaluations under these settings.
Anthology ID:
2025.acl-short.50
Volume:
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers)
Month:
July
Year:
2025
Address:
Vienna, Austria
Editors:
Wanxiang Che, Joyce Nabende, Ekaterina Shutova, Mohammad Taher Pilehvar
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
636–644
Language:
URL:
https://preview.aclanthology.org/landing_page/2025.acl-short.50/
DOI:
Bibkey:
Cite (ACL):
William Jurayj, Jeffrey Cheng, and Benjamin Van Durme. 2025. Is That Your Final Answer? Test-Time Scaling Improves Selective Question Answering. In Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers), pages 636–644, Vienna, Austria. Association for Computational Linguistics.
Cite (Informal):
Is That Your Final Answer? Test-Time Scaling Improves Selective Question Answering (Jurayj et al., ACL 2025)
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PDF:
https://preview.aclanthology.org/landing_page/2025.acl-short.50.pdf