This five-year research programme is motivated by the question: Why does the structure of government vary, and how does this affect the quality of democracy and governance? The programme estimates and explains the scope and depth of authority exercised by subnational governments and international governmental organizations (IGOs) from 1950 to 2010. This will allow deeper understanding of a major policy development multilevel governance, the dispersion of authority away from central states to subnational and supranational levels. While major institutions, including the World Bank, the European Parliament, and European Commission recommend multilevel governance, some policy analysts claim that multilevel governance exacerbates corruption, leads to gridlock, engenders moral hazard, constrains redistribution, obfuscates accountability, and wastes money. However, comparative information about how international and subnational government varies across countries and over time is lacking, and so it is not possible to discipline normative claims against evidence. The contribution of the research programme is threefold. First, it provides carefully constructed, comparative, and reliable estimates of subnational and international government for a wide range of countries over an extended time period. Second, it seeks to advance understanding of the causes of multilevel governance, building on the major theories in the field. Third, it provides a rigorous assessment of the consequences of multilevel governance. Theories of the causes and consequences of multilevel governance will be evaluated quantitatively and in a case study of government response to climate change.