用大模型评分+智能人工审核,高效选最优服务配置
Designing Service Systems from Textual Evidence
- 结合大模型打分与逆概率加权残差,纠正评估偏差
- 在40次试验中100%选对最佳模型,人工审核成本降低90%
- 适合需要高精度且人力成本高的服务系统优化场景
服务系统设计需在多种配置间选择——如最佳聊天机器人、最优路由策略或最有效的质量控制流程。许多服务系统的性能证据是文本数据(如客服对话记录、投诉描述、合规审查报告),而非传统优化方法依赖的数值指标。大语言模型(LLMs)可读取这些文本并生成标准化质量评分,但其评估存在随配置和实例变化的系统性偏差。人工专家评审准确但昂贵。本文研究如何在保证高置信度的前提下,最小化人工审核成本:自动化评估廉价但有偏,可选择性获取真实验证结果。我们将此建模为序列决策问题,每轮观测一个有偏代理评分,可额外付费获取人工验证。证明了仅用LLM会因臂相关偏差而失效,朴素的按需审计估计器可能渐近有偏。提出一种结合代理评分与逆倾向加权残差的估计器,并构建任意时间有效置信序列。所提算法PP-LUCB同时决定评估哪些配置及是否请求人工审核,聚焦于大模型最不可靠之处。证明其正确性并给出实例相关成本界,接近最优效率。在客户支持工单分类任务上,算法在40/40次试验中正确识别最佳模型,实现90%的审计成本削减。
原文摘要 · Abstract (English)
Designing service systems requires selecting among alternative configurations -- choosing the best chatbot variant, the optimal routing policy, or the most effective quality control procedure. In many service systems, the primary evidence of performance quality is textual -- customer support transcripts, complaint narratives, compliance review reports -- rather than the scalar measurements assumed by classical optimization methods. Large language models (LLMs) can read such textual evidence and produce standardized quality scores, but these automated judges exhibit systematic biases that vary across alternatives and evaluation instances. Human expert review remains accurate but costly. We study how to identify the best service configuration with high confidence while minimizing expensive human audits, given that automated evaluation is cheap but biased. We formalize this as a sequential decision problem where a biased proxy score is observed for every evaluation, and a verified outcome can be acquired selectively at additional cost. We prove that LLM-only selection fails under arm-dependent bias, and that naive selective-audit estimators can be asymptotically biased. We develop an estimator combining proxy scores with inverse-propensity-weighted residuals and construct anytime-valid confidence sequences. Our algorithm, PP-LUCB, jointly decides which alternatives to evaluate and whether to request human audits, concentrating reviews where the LLM judge is least reliable. We prove correctness and establish instance-dependent cost bounds showing near-optimal efficiency. On a customer support ticket classification task, our algorithm correctly identifies the best model in 40/40 trials while achieving 90\% audit cost reduction.
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