What Can We Learn About the Ideology of the Newest Supreme Court Justices?

In this article, we present a principled method for updating estimates of the ideology of Supreme Court justices based on each new vote they cast. We apply this method to the ideological positions of the newly appointed members of the Court: John Roberts, Samuel Alito, and Sonia Sotomayor. This approach allows us to gain not only an estimate of justices' ideologies but also a greater understanding of the level of uncertainty we should have about these values, including how much we can learn about a new justice's views after he or she has cast a given number of votes on the Court.