Courts of last resort in the American states are key settings for testing how institutions shape judicial behavior. A central input for that work is individual judges' preferences—ideal points—measured in policy space.

🧭 What Is Being Measured and Why It Matters

• Focus: individual judges' ideal points on a common ideological scale.
• Existing approaches: Brace, Langer, and Hall (2000) Party-Adjusted Judge Ideology and Bonica and Woodruff (2014) judicial CFscores.
• Goal: improve measurement by combining distinct information sources to better recover judges' latent preferences.

🛠️ How Votes and CFscores Were Combined

• Method: integrate Bonica and Woodruff's CFscores with item response theory (IRT) estimates of judicial voting behavior.
• Scope: all 52 state courts of last resort, covering 1995–2010.
• Key technical features:
• Dynamic estimation that allows judges' ideological leanings to change over time.
• Mapping of judges into a single common space for cross-court comparability.

🔎 Key Findings

• Leveraging two distinct sources of information—roll-call votes and CFscores—produces a superior estimation strategy compared to either existing measure alone.
• The combined measure outperforms Party-Adjusted Judge Ideology and CFscores in predicting judges' votes.
• The dynamic, common-space estimate enables tracking ideological shifts within and across state courts.

⚖️ Why This Matters for Judicial Politics

• The new measure provides researchers a more accurate, time-sensitive way to recover judicial preferences, strengthening inferences about how institutions and contexts influence state supreme court behavior.
• As a superior predictive tool, it offers practical value for research on judicial decision-making and comparative analyses across states.