Who refers most? Institutional incentives and judicial participation in the preliminary ruling system

By enabling the Court of Justice to engage domestic judges, the preliminary ruling mechanism is widely recognised to have played a major role in European integration. Yet both the incentives and motivation to cooperate with the Court of Justice are believed to vary significantly across domestic courts. We explore how domestic courts differ in their referral behaviour depending on the position they occupy in the juridical hierarchy using a novel dataset, which extends, complements and corrects data initially collected by Stone Sweet and Brunell (1998. ‘The European Court and the national courts: a statistical analysis of preliminary references, 1961–95’, Journal of European Public Policy 5 (1): 66–97). We find that first instance courts pioneered the use of the preliminary ruling procedure, but that appellate and peak courts subsequently overtook them. We explain these shifts by the combined effect of institutional consolidation, organisational design and legal rules. We argue that resort to Article 267 TFEU was initially ‘accidental’ but became institutionalised as more courts submitted references. This, in turn, allowed the division of labour underpinning the organisation of national judiciaries to reshape referral dynamics.