Whilst levels of judicial dissent have been analysed for different common law courts – including courts at both federal and state level in the United States – there has been little or no research on levels of dissent in those European constitutional courts which permit dissenting opinions. In this paper I investigate levels of dissent in nineteen constitutional courts in the United States, United Kingdom, Australia, Canada, South Africa, Iceland, Portugal, Spain, Germany, Chile, Slovenia, the Czech Republic, Romania, Hungary, Poland, Slovakia, Estonia, and Croatia. I examine the degree to which dissents on each court are comparable, and whether dissents on how to dispose of a case can be distinguished from dissents concerning rationes decidendi. I examine the impact of socio-legal background (societal litigiousness, legal family) institutional settings (judge appointment method, tenure) and the constellation of preferences of other actors (the number of veto players, their ideological range, and their political fragmentation). I test these impacts through an unbalanced panel design, and show which effects primarily concern differences between courts, and which features – such as caseload – primarily concern differences in dissent over time within courts.
