Group Decision Making on Appellate Panels: Presiding Justice and Opinion Justice Influence in the Israel Supreme Court

Appellate adjudication frequently involves small group decision making. Role responsibility theory and experimental evidence suggest that high status group members may disproportionately influence other members. A judicial panel's presiding justice and the justice who writes a case's opinion thus may influence other justices' votes. We compare justices' voting patterns in cases in which they presided and wrote opinions with their voting patterns when they did not preside or write opinions. The data consist of 1,410 mandatory jurisdiction criminal law cases decided by the Israel Supreme Court in 2006 and 2007. Voting patterns varied significantly with presiding and nonpresiding status. On average justices were 4.5% more likely to vote in their preferred direction when presiding than as mere panel members, which corresponds to an increase of about 28% given a baseline rate of voting for defendants of 16%. Justices' colleagues' voting patterns significantly changed when particular justices did and did not preside. Colleagues were 50% more likely to vote for defendants when one justice did not preside compared with when he did. Some justices' voting patterns varied based on opinion-writing status. This is likely due to the nonrandom process of opinion assignment.