Estimating Dynamic Ideal Points for State Supreme Courts

Abstract

Courts of last resort in the American states offer researchers considerable leverage to develop and test theories about how institutions influence judicial behavior. One measure critical to this research agenda is the individual judges' preferences, or ideal points, in policy space. Two main strategies for recovering this measure exist in the literature: Brace, Langer, and Hall's (2000, Measuring preferences of state supreme court judges, Journal of Politics 62(2):387–413) Party-Adjusted Judge Ideology and Bonica and Woodruff's (2014, A common-space measure of state supreme court ideology, Journal of Law, Economics, & Organization, doi: 10.1093/jleo/ewu016) judicial CFscores. Here, we introduce a third measurement strategy that combines CFscores with item response (IRT) estimates of judicial voting behavior in all fifty-two state courts of last resort from 1995 to 2010. We show that leveraging two distinct sources of information (votes and CFscores) yields a superior estimation strategy. Specifically, we highlight several key advantages of the combined measure: (1) it is estimated dynamically, allowing for the possibility that judges' ideological leanings change over time and (2) it maps judges into a common space. In a comparison against existing measurement strategies, we find that our measure offers superior performance in predicting judges' votes. We conclude that it is a valuable tool for advancing the study of judicial politics.

The Government Deference Dimension of Judicial Decision Making: Evidence from the Supreme Court of Norway

“…These kinds of inferences are found whenever appointing party is used as a proxy for judicial preferences. Previous studies which have inferred judges' preferences on a left-right scale have included multiple studies of the US Supreme Court (Martin & Quinn 2002) and American state supreme courts (Windett et al 2015), as well as studies of European constitutional courts (Hanretty 2012(Hanretty , 2014. This focus on left/right preferences in political science is understandable: the left/right spectrum structures most of electoral politics in advanced industrial democracies, and political scientists who are interested in courts tend to be most interested in 'politicised' courts, which are more likely to reflect the same preference structures found in electoral politics.…”

Judicial Independence on Unelected State Supreme Courts

“…Judicial selection method is coded for each justice in each year. 9 To approximate a justice's policy preferences, I use the dynamic ideal points for state supreme court justices developed by Windett, Harden, and Hall (2015). This measure of ideology combines CFScores (Bonica and Woodruff 2015) with item response estimate of judicial voting behavior.…”

A Common-Space Scaling of the American Judiciary and Legal Profession

“…First, we show that the ideologies of lawyers arguing cases before the Supreme Court closely track the directionality of case outcomes. Second, and 1 Although not our focus here, state high courts sometimes hear cases in groups large enough to be scaled based on votes (Windett, Harden, and Hall 2015). Even so, assumptions are required in order to compare votes-based estimates across states or jurisdictions.…”