Rankings and Ratings: Instructions for Use

Multidimensional measures (composite indicators, indices, ratings, league tables) can effectively underpin the development of data-driven narratives in support to policy. A controversy surrounds the use of these measures. We review some good and bad practices from the recent literature. We then discuss briefly a decalogue to develop a multidimensional measure. We argue in favor of a multi-modeling approach to represent different scenarios in the construction of an aggregate measure prior to drawing recommendations for policy making. Finally, we try to establish a link between the analytic use of well-designed aggregate measures and the development of a robust culture of evaluation of policies based on evidence. An application of these concepts and tools to the Rule of Law index developed by the World Justice Project is given.