Does the Judge Matter? Exploiting Random Assignment on a Court of Last Resort to Assess Judge and Case Selection Effects

We study 1,410 mandatory jurisdiction and 48 discretionary jurisdiction criminal law case outcomes in cases appealed to the Israel Supreme Court in 2006 and 2007 to assess influences on case outcomes. A methodological innovation is accounting for factors—case specialization, seniority, and workload—that modify random case assignment. To the extent one accounts for nonrandom assignment, one can infer that case outcome differences are judge effects. In mandatory jurisdiction cases, individual justices cast 3,986 votes and differed by as much as 15 percent in the probability of casting a vote favoring defendants. Female justices were about 2 to 3 percent more likely than male justices to vote for defendants but this effect is sensitive to including one justice. Defendant gender was associated with outcome, with female defendants about 17 percent more likely than male defendants to receive a favorable vote on appeal. Our data's samples of mandatory and discretionary jurisdiction cases allow us to show that studies limited to discretionary jurisdiction case outcomes can distort perceptions of judges' preferences. Justices' ordinal rank in rate of voting for defendants or the state was uncorrelated across mandatory and discretionary jurisdiction cases. For example, the justice who sat on the most criminal cases was the fourth (of 16 justices) most favorable to the state in mandatory jurisdiction cases but the 12th most favorable in discretionary jurisdiction cases. This result casts doubt on some inferences based on studies of judges on discretionary jurisdiction courts, such as the U.S. Supreme Court, in which only discretionary case outcomes are observed.