提出时间约束的引文上下文检索方法，避免未来引用干扰结果
Fenced Citation-Context Retrieval for Case Law: Temporal Leakage and Degree Control Across Two Jurisdictions
- 用时间过滤器限制引文上下文仅包含查询案发前的引用
- 在欧洲人权法院数据集上超越强基线，提升14.9%的检索增益
- 适合法律信息检索与司法决策支持系统开发者使用
先例案件检索（PCR）旨在识别与查询案件事实相关的判例。引文上下文（incoming citation context）——后案引用时描述某案的文本——是重要相关性信号，但现有评估未加时间约束，导致检索器被赋予查询案发生后才出现的引用。本文提出一种无参数的时间篱笆检索器，将BM25与仅包含查询案发生前引用的引文上下文结合，并引入时间准入分解以量化“幻影比例”：即引文上下文增益中归属于未知预发引用的部分。实验覆盖美国联邦法院（CLERC）与欧洲人权法院（ECtHR-PCR）两个法域。在ECtHR-PCR数据集上，无需训练，该方法在全召回层级均优于强基线；时间准入分解显示，未加时间约束的引文上下文增益中，14.9%（验证集）归因于未知预发引用。因此，引文上下文检索必须进行时间约束和度数控制，方可正确解释其报告性能提升。
原文摘要 · Abstract (English)
Prior case retrieval (PCR) aims to identify the precedent cases relevant to the facts of a query case. Incoming citation context, the text with which later cases characterize a case when citing it, is a powerful relevance signal, yet it is typically evaluated without a temporal constraint, so the retriever is credited with citations made after the query. We introduce a temporally fenced retriever with no learned parameters that augments BM25 with incoming citation context restricted to citations predating the query, together with a temporal-admission decomposition that quantifies the phantom fraction: the share of a citation-context gain attributable to citations not known to predate the query. Experiments span two jurisdictions, U.S. federal (CLERC) and European (ECtHR-PCR) case law. On ECtHR-PCR, without any training, the fenced retriever outperforms a strong degree-controlled baseline across the full recall ladder, and a temporal-admission decomposition attributes 14.9% (validation) of an unfenced citation-context gain over BM25 to citations not known to predate the query. Citation-context retrieval must therefore be temporally fenced and degree-controlled before its reported gains can be interpreted.
Thank you to arXiv for use of its open access interoperability. PaperDance 不是 arXiv 官方产品；中文卡片由大模型生成，请以原文为准。