(multiple possibilities) - Indication of the quality of the data based on the following categories: i. Central statistical agencies - Data are the result of work of central statistical agencies. ii. Historical reconstructions - Data are the result of historical reconstructions making use of the methods and the broad range of data that are also used by central statistical agencies

General references

Carmen M. Reinhart & Kenneth S. Rogoff, "Debt-to-GDP Ratios", http://www.reinhartandrogoff.com/data/browse-by-topic/topics/9/. Consulted: April 5, 2012.

- World Bank, "Central government debt, total (% of GDP)", http://data.worldbank.org/indicator/GC.DOD.TOTL.GD.ZS. Consulted: April 10, 2012.

In 2010, the Netherlands Organisation for Scientific Research (NWO) awarded a subsidy to the Clio Infra project, of which Jan Luiten van Zanden was the main applicant and which is hosted by the International Institute of Social History (IISH). Clio Infra has set up a number of interconnected databases containing worldwide data on social, economic, and institutional indicators for the past five centuries, with special attention to the past 200 years. These indicators allow research into long-term development of worldwide economic growth and inequality.

Global inequality is one of the key problems of the contemporary world. Some countries have (recently) become wealthy, other countries have remained poor. New theoretical developments in economics - such as new institutional economics, new economic geography, and new growth theory - and the rise of global economic and social history require such processes to be studied on a worldwide scale. Clio Infra provides datasets for the most important indicators. Economic and social historians from around the world have been working together in thematic collaboratories, in order to collect and share their knowledge concerning the relevant indicators of economic performance and its causes. The collected data have been standardized, harmonized, and stored for future use. New indicators to study inequality have been developed. The datasets are accessible through the Clio Infra portal which also offers possibilities for visualization of the data. Clio Infra offers the opportunity to greatly enhance our understanding of the origins, causes and character of the process of global inequality.