Does Group Familiarity Improve Deliberations in Judicial Teams? Evidence from the German Federal Court of Justice

Collegiality plays a central role in judicial decision‐making. However, we still lack empirical evidence about the effects of collegiality on judicial decision‐making. In this article, I argue familiarity, an antecedent to collegiality, improves judicial deliberations by encouraging minority dissent and a more extensive debate of different legal viewpoints. Relying on a novel dataset of 21,613 appeals in criminal cases at the German Federal Court of Justice between 1990 and 2016, I exploit quasi‐random assignment of cases to decision‐making groups to show that judges' pairwise familiarity substantially increases the probability that judges schedule a main hearing after first‐stage deliberations. Group familiarity also increases the length of the justification of the ruling. The findings have implications for the way courts organize the assignment of judges to panels.