Stephen J. Choi, G. Mitu Gulati, Eric A. Posner; Professionals or Politicians: The Uncertain Empirical Case for an Elected Rather than Appointed Judiciary. J Law Econ Organ 2010; 26 (2): 290-336. doi: 10.1093/jleo/ewn023
Conventional wisdom holds that appointed judges are superior to elected judges because appointed judges are less vulnerable to political pressure. However, there is little empirical evidence for this view. Using a data set of state high court opinions, we construct measures for three aspects of judicial performance: effort, skill, and independence. The measures permit a test of the relationship between performance and the four primary methods of state high court judge selection: partisan election, non-partisan election, merit plan, and appointment. Appointed judges write higher quality opinions than elected judges do, but elected judges write more opinions, and the evidence suggests that the large quantity difference makes up for the small quality difference. In addition, elected judges are not less independent than appointed judges. The results suggest that elected judges focus on providing service to the voters, whereas appointed judges care more about their long-term legacy as creators of precedent.
If the state has a problem with judicial impartiality, it is largely one the state brought upon itself by continuing the practice of popularly electing judges.
Justice O'Connor, concurring in Republican Party of Minn. v. White, 536 U.S. 765, 792 (2002).