How judges’ social identity impacts reversal decisions: evidence from the transitory promotion of judges

Several studies have underscored the significance of familiarity and collegiality in shaping judicial behavior in US federal courts. However, the distinct features of the US judicial system limit the ability to formulate a general theory. This research draws on 84,335 appellate decisions from Taiwanese courts to examine the role of familiarity in a career judge system. In Taiwan, lower court judges are transitorily promoted to appellate courts for 3 years, after which they typically return to their district courts before some of them are permanently promoted. By comparing their reversal patterns during temporary and subsequent permanent promotions to those of permanent appellate judges, we find that transitorily promoted judges reverse less frequently, and judges generally favor district courts where they have previously served. Social identity is likely a key explanatory factor. The size, diversity, and random allocation of cases in our dataset strengthens the generality of judicial behavior theories.