Revisiting the Ideology Rankings of Supreme Court Justices

Published in 2015. In the Journal of Legal Studies 44: S295-S317

Lee Epstein
William M. Landes
Richard A. Posner

This paper addresses the two main criticisms made by Cass Sunstein of the ideological rankings of justices in our book on federal judicial behavior. The first was that ranking justices from different time periods is problematic because the justices faced a different mixture of cases. The second questioned our implicit assumption that cases are fungible for the purpose of calculating a justice's ideology. To address the first criticism, we use the votes of moderate justices to create an adjusted voting index for each justice that controls for the influence of nonideological factors (for example, changes in the characteristics of cases). We respond to the second criticism by ranking justices on the basis of their votes in the most significant and controversial cases—5-4 decisions and cases reported in the New York Times. Overall, these adjustments result in only minor changes in the rankings in our book.

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