Do ECJ judges all speak with the same voice? Evidence of divergent preferences from the judgments of chambers

A considerable body of scholarly work has asserted that the ECJ's institutional independence has implied behavioural independence: in short, that the ECJ has pursued a pro-integration agenda perhaps at odds with national governments' preferences. But, inside the black box of the court's collective decisions, do judges share a common preference for expanding the authority of the Court and EU generally? While individual behaviour is not directly observable, the ECJ's system of chambers provides a potentially valuable window on the impact of individual decisions by subsets of the judges. I develop a statistical model, extending the item-response model to account for selective participation in decisions, to find evidence of individual behaviour in the collective judgments. Results for ECJ cases show that judges do not share uniform preferences, suggesting that institutional independence has provided cover for the court, and that judges' preferences lie on a continuum from Europhilia to Euroscepticism.