Judicial Citations & Common Law Evolution: A Chronometric Analysis of High Court Citations

Abstract

All common law systems draw from the past. As judges draft opinions, they cite to relevant case law to guide their decisionmaking. These citations provide a record of how new legal developments draw on previous holdings. This Article presents the first thorough data-driven analysis of how different patterns of drawing from the past are related to the influence a judicial opinion has on future legal developments.

We draw on large datasets of opinions from the U.S. Supreme Court, the Supreme Court of Canada, and the Supreme Court of India to show that there are previously undiscovered commonalities in the way that common law systems evolve. By focusing on two measures of citation age — distance (or average age) and dispersion (or variance of ages cited) — we show that there is one type of case that is strikingly more likely to go on to become highly influential. Cases featuring low distance and high dispersion are more than twice as likely as other types of cases to go on to be “hit” opinions, garnering many citations.

Our findings help us better understand how common law high courts draw from the past to support important legal holdings. In addition to our substantive findings, this Article helps show the promise of computational legal studies by integrating large datasets into a novel analysis and generating findings that otherwise would have remained undiscovered.

Keywords: Legal Evolution, Judicial Behavior, Citation Analysis, Computational Legal Studies

JEL Classification: K40, K41