Do Constitutional Courts Write Their Opinions Differently Under Public Scrutiny? Applying NLP Methods to Uncover Argument Structure in Judicial Texts

How does public scrutiny affect the opinion-formation of highest courts? Established scholarship shows that public opinion impacts the outcome of judicial decision-making. However, while the focus rests with outcomes of decisions, the impact of public scrutiny on the whole opinion-formation remains puzzling. This is why I present a novel approach to assess the causal effects of public scrutiny on opinion writing and the quality of decisions taking judicial opinion-formation serious. In particular, I introduce the analyses of argumentation structures from natural language processing to judicial politics. The written decisions of courts are segmented into internally coherent argumentative units which constitute the opinion formation of the court. For each segment I assess the deliberative and argumentative quality of the court’s ruling based on length, complexity, use of precedence and similarity to written briefs. I argue that oral hearings increase public attention and moderate the interaction of judges, petitioners, political and societal actors participating in hearings. The broader attention introduced by oral hearings incentivises judges to improve the deliberative quality of written opinions. Thus I expect courts to argue each point of the discussion in more detail, making use of more precedence cases and literature to support their argument and addressing briefs more closely. To test my argument, I apply my approach to the whole text of decisions published by the German Federal Constitutional Court between 1972 to 2019. The court is a role-model for many highest courts with constitutional review powers and hearings are a common feature of court’s decision-making.