How Would Judges Compose Judicial Panels? Theory and Evidence from the Supreme Court of Israel

How would judges compose judicial panels, if they could? We focus on a procedure in the Supreme Court of Israel that allows each justice to compose three-justice panels, collecting an original database of decisions in this procedure. The data reveal strong bias in justices’ panel composition. A Gini coefficient measuring the extent of inequality in each justice's panel composition, which runs between 0 (total equality) and 1 (total inequality), is 0.82 on average, which contradicts the random composition theory. The high variance in the choice of panel members contradicts the professional composition theory. The data support the idea that justices compose panels strategically, and accordingly the data uncover justices’ revealed preference for panel members. We use the data to depict the relationships within the Supreme Court of Israel, and identify three groups of justices. Lastly, we show that justices who were selected by the current Chief Justice under the above procedure, before she became Chief Justice, are more likely to sit on panel with her in ordinary hearings after she became Chief Justice. Since the Chief Justice has the legal authority to compose ordinary panels, this is also consistent with strategic panel composition.