On Estimating Personality Traits of US Supreme Court Justices

Psychological scholarship on personality is uniting with political science to redefine existing theories. This is clearly the case with research on judicial behavior and the US Supreme Court. But if this new approach is to survive and thrive, it must employ measures equal to the task. We show that Supreme Court Individual Personality Estimates, which seek to estimate justices’ personalities by examining their concurring opinions, suffer from a number of important methodological deficits that critically limit their usefulness. We briefly discuss what kinds of improved personality measures scholars should use instead and offer an improved set of estimates for one trait with an application that demonstrates our cautionary tale.