Comparative methods for measuring judicial ideology and behavior

We explore various approaches to the measurement of judicial ideology. Those include classic and well-established as well as the state of the art. Our main focus is on measurement schemes appropriate for judicial systems outside of the USA, as the latter is already well examined. The methods surveyed include proxy variables, expert opinions, as well as methodological frameworks using behavioral approaches. The latter include quantitative approaches using vote counting, statistical methods mostly utilizing Item Response Theory (IRT), and automatic, semi-automatic or manual analysis of judicial texts. We pay special attention to the differences between various legal systems, which poses challenges for using some of the methods in certain cases. Such measurements schemes also differ on the unit of analysis - either individual justices or the court as a whole. The latter allows comparative estimation of judicial ideology across different countries.