Is That Your Final Answer? Test-Time Scaling Improves Selective Question
  Answering
Authors: name: William Jurayj; name: Jeffrey Cheng; name: Benjamin Van Durme
Published: 2025-02-19 18:58:31

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.