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LLM confidence estimates flawed by sparsity, new paper finds

A new research paper published on arXiv highlights significant limitations in how large language models (LLMs) estimate confidence for classification tasks. The study found that common methods like verbalization produce overly sparse outputs, with models like Qwen3-32B offering very few unique confidence values. This sparsity critically impacts evaluation metrics, altering model rankings based on interpolation choices. The researchers propose a new method called 'verbalization logprobs' which addresses sparsity and improves confidence estimation without increasing inference costs. AI

IMPACT Highlights critical issues in LLM confidence estimation, potentially impacting reliability in classification tasks and influencing future evaluation methodologies.

RANK_REASON Research paper published on arXiv detailing evaluation methods for LLMs. [lever_c_demoted from research: ic=1 ai=1.0]

Read on arXiv cs.CL →

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LLM confidence estimates flawed by sparsity, new paper finds

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Research paper published on arXiv detailing evaluation methods for LLMs. [lever_c_demoted from research: ic=1 ai=1.0]
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COVERAGE [1]

  1. arXiv cs.CL TIER_1 English(EN) · Elena Merdjanovska, Omar Zaidan, Andreas R\"uckl\'e ·

    Evaluation Pitfalls and Sparsity Limitations in LLM-based Confidence Estimates for Classification

    arXiv:2608.04899v1 Announce Type: new Abstract: Confidence estimation is essential when LLMs are used for classification, indicating when predictions can be trusted. However, common approaches such as verbalization produce extremely sparse outputs. For instance, Qwen3-32B verbali…