arXiv:2603.04417cs.CL2026-03

不同大模型对相同答案评分差异大,温度也影响稳定性。

Same Input, Different Scores: A Multi Model Study on the Inconsistency of LLM Judge

  • 用五款主流模型在相同问答对上反复评分,测试一致性
  • 同一输入得分差可达30%以上,温度为0时仍不稳定
  • 适合做自动评估的公司需警惕评分不可靠问题

大型语言模型作为自动化评估工具(即LLM-as-a-judge)在研究与企业场景中日益普及。本研究系统评估了GPT-4o、GPT-4o-mini、Gemini-2.5-Flash、Claude-Haiku-4.5和Claude-Sonnet-4.5五款模型,在两种温度设置下对检索增强生成(RAG)系统中真实企业问答对的评分稳定性。结果发现:即使在温度=0时,各模型评分仍存在显著波动,完整性评分波动最大;跨模型比较显示评分严格度与理解风格系统性差异,导致相同答案获得不同分数;降低温度可提升GPT-4o和Gemini的稳定性,但对Anthropic模型效果有限且不一致。该现象影响企业流程中的路由、筛选、准入与质量控制,引发公平性、可复现性与运行可靠性担忧。研究呼吁加强监控、鲁棒解析及人机协同评估策略以保障生产环境中的可信使用。

原文摘要 · Abstract (English)

Large language models are increasingly used as automated evaluators in research and enterprise settings, a practice known as LLM-as-a-judge. While prior work has examined accuracy, bias, and alignment with human preferences, far less attention has been given to how consistently LLMs assign numerical scores, an important concern for many production workflows. This study systematically evaluates scoring stability across five commonly used models, GPT-4o, GPT-4o-mini, Gemini-2.5-Flash, Claude-Haiku-4.5, and Claude-Sonnet-4.5, two temperature settings, and real enterprise question-answer pairs drawn from a retrieval-augmented generation (RAG) system. We address three questions: how stable a model's scores are across repeated runs, how differently models score identical inputs, and how temperature affects scoring consistency. Temperature controls the determinism of an LLM's output. Despite expectations of stability at temperature=0, we observe substantial variability across models, with completeness scoring showing the largest fluctuations. Cross-model comparisons reveal systematic differences in strictness and interpretive style, leading to divergent ratings for the same answers. Lower temperatures improve stability for some models, notably GPT-4o and Gemini, but have limited or inconsistent effects for Anthropic models. These findings have important implications for enterprise pipelines that rely on LLM-generated scores for routing, triage, gating, or quality control. Identical inputs can receive different scores depending on model, family, or temperature, raising concerns around fairness, reproducibility, and operational reliability. Our results highlight the need for monitoring, robust parsing, and hybrid human-LLM evaluation strategies to ensure dependable use of LLM-as-a-judge in production environments.

大模型评估评分一致性RAGLLM-as-a-judge

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