"Indicator-based governance assessments support the precise description of differences and similarities among countries. But they also simplify a much more complex empirical reality by focusing on its quantifiable aspects and by aggregating its different components and interrelations into abstract numbers. To initiate a reflective debate about the utility of such indicators, this paper presents a new indicator project that links numerical ratings and rankings with comparative studies, the Bertelsmann Transformation Index (BTI). The BTI is a global ranking that examines the political management of societal change in 119 countries on the way to a market-based democracy. The paper explains why such an assessment may be useful for Southeastern Europe, a region situated between the legacies of war-ridden authoritarian regimes and the future of membership in the European Union. We argue that EU accession and international agreements on questions of contested statehood are important for Southeastern Europe but should not distract attention from the quality of democracy and market economy in each country of the region. We then discuss the conceptualization of democracy, market economy and governance in order to derive criteria and questions for the BTI. The BTI's methodology of measurement and aggregation is explained in detail. These sections show that the BTI differs from other indices by focusing on the management performance of political actors, by using broader, more demanding concepts of democracy and market economy and by relying mostly on self-collected empirical evidence. In contrast to numerical ratings on the one hand or purely qualitative comparisons of countries on the other hand, the BTI allows readers to simultaneously compare countries and to familiarize themselves with the state of affairs in individual countries. Run by non-governmental organizations, the BTI does not depend on political mandating or the consensus requirements of international organizations. The BTI and similar assessments may initiate public discourses on better governance and encourage governments to engage in peer review mechanisms and evidence-based policy making." (author's abstract