The preliminary reference procedure allows national courts to refer questions surrounding the clarification of EU law to the Court of Justice of the European Union (CJEU). In the past, the CJEU has often seized on these opportunities to advance social and economic integration in Europe through its jurisprudence. Unsurprisingly though, not all national courts appear equally eager to invest the extra effort and refer their cases to the CJEU. In their article “Who refers most? Institutional incentives and judicial participation in the preliminary ruling system” published in the Journal of European Public Policy, Arthur Dyevre, Monika Glavina and Angelina Atanasova argue that in the face of a higher caseload, judges at national first-instance courts tend to afford less time per case than their colleagues higher up in national judicial hierarchies. Busier schedules would then lead us to expect lower referral rates among lower courts. To study the drivers of national courts’ referral rates to the CJEU, Arthur, Monika and Angelina extended, revised and supplemented existing data. Their evidence shows that while lower courts ‘accidentally’ pioneered the use of the preliminary reference procedure early on, higher appellate courts have established themselves as the most prominent referring courts over time. This pattern suggests that as lower courts kick-started an institutionalisation of EU law, higher courts had to divert their attention to supranational law, which then “allowed the division of labour underpinning the organisation of national judiciaries to reshape referral dynamics.”