arXiv:2505.21772cs.CL2025-05EMNLP被引 24

通过检测模型内部表示对扰动的稳定性,提升大模型预测可信度。

Calibrating LLM Confidence by Probing Perturbed Representation Stability

  • 用对抗性扰动测试模型隐藏状态的响应稳定性,提取鲁棒特征。
  • 在多个大模型上使校准误差降低55%,准确率提升5个百分点。
  • 无需训练、适配性强,适合需高可信度的应用场景。

大语言模型(LLMs)的置信度失准影响其可靠性,亟需精准的置信度估计。本文提出CCPS(Calibrating LLM Confidence by Probing Perturbed Representation Stability),通过在最终隐藏状态施加定向对抗扰动,提取模型对扰动的响应特征,并用轻量分类器预测答案正确性。在8B至32B参数的Llama、Qwen、Mistral等模型上,使用MMLU和MMLU-Pro基准进行多选与开放题测试。结果表明,相较于最强现有方法,CCPS在四个LLM和三个MMLU变体上,将期望校准误差降低约55%,布里尔得分减少21%,准确率提升5个百分点,精确率-召回率曲线下面积增加4个百分点,受试者工作特征曲线下面积提高6个百分点。该方法高效、普适且更精准,显著增强模型可信度。

原文摘要 · Abstract (English)

Miscalibration in Large Language Models (LLMs) undermines their reliability, highlighting the need for accurate confidence estimation. We introduce CCPS (Calibrating LLM Confidence by Probing Perturbed Representation Stability), a novel method analyzing internal representational stability in LLMs. CCPS applies targeted adversarial perturbations to final hidden states, extracts features reflecting the model's response to these perturbations, and uses a lightweight classifier to predict answer correctness. CCPS was evaluated on LLMs from 8B to 32B parameters (covering Llama, Qwen, and Mistral architectures) using MMLU and MMLU-Pro benchmarks in both multiple-choice and open-ended formats. Our results show that CCPS significantly outperforms current approaches. Across four LLMs and three MMLU variants, CCPS reduces Expected Calibration Error by approximately 55% and Brier score by 21%, while increasing accuracy by 5 percentage points, Area Under the Precision-Recall Curve by 4 percentage points, and Area Under the Receiver Operating Characteristic Curve by 6 percentage points, all relative to the strongest prior method. CCPS delivers an efficient, broadly applicable, and more accurate solution for estimating LLM confidence, thereby improving their trustworthiness.

置信度校准大模型对抗扰动可靠性

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