Informal Judicial Hierarchies: Case Assignment and Chamber Composition at the European Court of Justice

Abstract

Is there a rationale behind non-random case assignment at the European Court of Justice (ECJ)? This paper makes two contributions to the emerging literature on the internal organization of the Court. On a theoretical level, I argue that the flexible system of case assignment effectively creates an “informal judicial hierarchy”, allowing the majority of the judges to curb the influence of judges with outlier preferences. While such an informal judicial hierarchy potentially carries a number of negative implications, I argue that the ECJ needs it in order to ensure both the consistency of its decision-making and its effectiveness as an institution. In its empirical part, the paper addresses the question whether there is evidence of such strategic behavior on the part of the majority of judges. Using Monte Carlo simulations, I first show that the system of chamber assignment in the time period 2009-2012 effectively reduced the variance of the median judges in proceedings before the Court as compared to a hypothetical system of chamber assignment as it is featured, for example, at the U.S. Federal Courts of Appeals. Second, I develop a test to determine whether this reduction in the variance of median judges is due to strategic behavior on the part of the majority of judges. I find weak evidence in favor of the hypothesis that such strategic behavior takes place.