Mandatory Retirement for Judges Improved Performance on U.S. State Supreme Courts

Anecdotal evidence often points to aging as a cause for reduced work performance. This paper provides empirical evidence on this issue in a context where performance is measurable and there is variation in mandatory retirement policies: U.S. state supreme courts. We find that introducing mandatory retirement reduces the average age of working judges and improves court performance, as measured by output (number of published opinions) and legal impact (number of forward citations to those opinions). Consistent with aging effects as a contributing factor, we find that older judges do about the same amount of work as younger judges, but that work is lower-quality as measured by citations. However, the effect of mandatory retirement on performance is much larger than what would be expected from the change in the age distribution, suggesting that the presence of older judges reduces the performance of younger judges