Measuring Policy Change in the U.S. Supreme Court

Measuring the U.S. Supreme Court's policy changes is complicated by change in the content of the cases that come before the Court. I adapt from earlier scholarship a method to correct for changes in case content and use this method to measure change in the Court's support for civil liberties in the 1946–85 terms. Analysis based on this method indicates that because of changes in case content, the average difficulty of reaching a pro-civil liberties result varied during that period. With corrections for case difficulty, the Warren Court of the 1950s appears to have been more conservative, and the Burger Court more liberal, than patterns of case outcomes themselves suggest. This method, while imperfect, has utility for the measurement of policy change in the Supreme Court and other institutions and thus can serve as a building block in analyses of the processes and determinants of change.