Mandatory Retirement for Judges Improved the Performance of US State Supreme Courts

This paper provides evidence on how mandatory retirement influences judge performance using reforms in US state supreme courts as a natural experiment. We find that introducing mandatory retirement improves court performance as measured by output (number of opinions) and legal influence (number of citations to opinions). While older judges are cited less than younger judges, the effect of mandatory retirement is larger than what is expected from a change in the age distribution. We find some evidence that the additional effect is due to selective attrition and that the presence of older judges reduces the performance of younger judges.