Original
Continuity and change in US legal tradition: Evidence from judicial citation communities
Abstract
Legal doctrine is often described as evolving case by case while preserving coherent legal traditions. We introduce a method for identifying and tracing such traditions by applying the Louvain community-detection algorithm to the complete U.S. federal judicial citation graph (1790-2024; 760,000 opinions linked by 8.3 million citations). The resulting citation communities are unsupervised, blind to court labels and topical taxonomies, yet they form meaningful empirical groupings: In validation exercises, they recover known institutional structure and capture coherent substantive and procedural approaches to law. Using these communities as empirical units, we study how legal traditions evolve and respond to legislative change. We show that the introduction of pivotal federal statutes shifts citation patterns toward newer precedent, indicating that legislation can disrupt established traditions and redirect the development of case law.
中文
美国法律传统的连续性与变迁：来自司法引用社区的证据
摘要
法律教义常被描述为在逐案演进的同时维持着连贯的法律传统。我们引入一种识别和追踪此类传统的方法，即将Louvain社区发现算法应用于完整的美国联邦司法引用图谱（1790—2024年；76万份判决意见，由830万条引用相连接）。由此得到的引用社区是无监督的，且对法院标签和主题分类不可见，但它们形成了有意义的经验分组：在验证性分析中，它们能够恢复已知的制度结构，并捕捉到对法律连贯的实体性与程序性处理方式。以这些社区作为经验单元，我们研究法律传统如何演变并回应立法变化。我们表明，关键联邦法规的出台会使引用模式转向更新的先例，这表明立法能够打破既有传统并重新引导判例法的发展。
关键词
司法引用网络、法律传统、判例法、联邦司法、社区发现、立法变迁、先例、美国法律