This Article is an empirical study of what we call citation stickiness. A citation is sticky if it appears in one of the parties' briefs and then again in the court's opinion. Imagine that the parties use their briefs to toss citations in the court's direction. Some of those citations stick and appear in the opinion—these are the sticky citations. Some of those citations don't stick and go unmentioned by the court—these are the unsticky ones. Finally, some sources were never mentioned by the parties yet appear in the court's opinion. These authorities are endogenous—they spring from the court itself. In a perfect adversarial world, the percentage of sticky citations in courts' opinions would be something approaching 100%. The parties would discuss the relevant authorities in their briefs, and the court would rely on the same authorities in its decisionmaking. Spoiler alert: our adversarial world is imperfect. Endogenous citations abound in judicial opinions and parties’ briefs are brimming with unsticky citations. So we crunched the numbers. We analyzed 325 cases decided by the federal courts of appeals. Of the 7552 cited cases in those opinions, more than half were never mentioned in the parties' briefs. But there's more—in the article, you’ll learn how many of the 23,479 cited cases in the parties' briefs were sticky and how many were unsticky. You’ll see the stickiness data sliced and diced in numerous ways: by circuit, by case topic, by an assortment of characteristics of the authoring judge. Read on!

This article begins by describing the structure of the appellate system in New York state, introducing the features of the typical New York pothole law, and summarizing the New York cases that set the substantive and procedural background for a discussion and analysis of judicial drift.