Sir Hans Wolfgang Singer (29 November 1910 – 26 February 2006) was a development economist best known for the Singer-Prebisch thesis, which states that the terms of trade move against producers of primary products. He is one of the primary figures of heterodox economics.
Singer was born in Elberfeld, Germany in 1910. A German Jew, Singer had intended to become a medical doctor before being inspired to study economics after attending a series of lectures by prominent economists Joseph Schumpeter and Arthur Spiethoff in Bonn. Singer fled the rise of Adolf Hitler in 1933, arriving in the United Kingdom as a refugee. In 1933, Schumpeter convinced John Maynard Keynes of Cambridge University to accept Singer as one of his first PhD candidates, and Singer received his doctorate in 1936. Under Keynes, he produced two papers in 1937 and 1940 studying unemployment. Keynes also helped secure Singer's speedy release after his former student was interned by the British government at the start of the Second World War. In 1938, Singer applied for British citizenship, listing as references Keynes, William Beveridge, William Temple and the vice-chancellor of Manchester University. His request was granted in 1946.
In 1947, he was one of the first three economists to join the new Economics Department of the United Nations, in which he remained for the next two decades. During his time at the United Nations, Singer was the Director of the Economic Division of the United Nations Industrial Development Organization (UNIDO), Director of the United Nations Research Institute for Social Development (UNRISD), and was closely involved in the creation of the Bretton Woods Framework and the post-World War II international financial institutions.
He published a 1950 empirical study examining the costs of international trade, drawing criticism from fellow economists Jacob Viner and Gottfried Haberler. The led to his famous co-credit with Raul Prebisch for the Prebisch-Singer hypothesis. However, the two economists did not collaborate, having come to similar conclusions separately. Singer's supporters are quick to point out that it appears that Singer wrote down the thesis before the more well-known Prebisch. The fundamental claim of the hypothesis is that, in a world system in which poorer nations specialize in primary products such as raw minerals and agricultural products that are then shipped to industrialized nations that, in turn, make advanced products to be sold to poorer nations, all of the benefits of international trade will go to the wealthy nations.
As a result of this deduction Singer was a passionate advocate for increased foreign aid in a variety of forms to the developing world to offset the disproportionate gain to developed nations of trade. He attempted to create a 'soft-loan' fund, which would offer loans at interest rates below market rates to be administered by the United Nations, but was systematically blocked by the United States and the United Kingdom, who wished to retain control of money flowing out of the UN. He was thus considered "one of the wild men of the UN" by Eugene R. Black of the World Bank and American Senator Eugene McCarthy. His ideas were influential in the establishment of the Bank's International Development Association, the United Nations Development Programme and the World Food Programme.
Fellow economist Sir Alec Cairncross has said of Singer that "There are few of the developing countries that he has not visited and still fewer that he has not advised. He must have addressed a wider variety of academics and a wider variety of places about a wider variety of subjects than any other economist, living or dead." Singer, like Prebisch, was influential on Neo-Marxist development theorists such as Paul Baran and Andre Gunder Frank. However, he was not normally considered a Neo-Marxist himself, nor did he consider himself one.
In 1969, he left the UN to join the influential Institute of Development Studies (IDS) at the University of Sussex in England. He produced about 30 books under his name and nearly 300 other publications. The International Institute of Social Studies (ISS) awarded its Honorary Fellowship to Hans Singer in 1977. Singer was knighted by Queen Elizabeth II in 1994. In 2001 the UN World Food Program awarded him the Food for Life award in recognition of his contribution to the battle against world hunger.  In November 2004, Singer was awarded the first Lifetime Achievement Award from the Development Studies Association. 
Singer died in Brighton, UK on 26 February 2006.
In commemoration and in honour of Sir Hans Singer the German Development Institute / Deutsches Institut für Entwicklungspolitik (DIE) and the Institute of Development Studies initiated the „Hans Singer Memorial Lecture on Global Development“, which alternates between Bonn and Brighton on an annual basis. The first Memorial Lecture was given by the renowned development economist Paul Collier of the University of Oxford in May 2009 in Bonn. The second Lecture was held in October 2010 in Brighton with Jomo Kwame Sundaram, Assistant Secretary General of the United Nations Economic Commission for Africa (UNECA). The third Memorial Lecture was given by Professor Stephen Chan, OBE of the School of Oriental and African Studies at University of London in November 2011 at the German Development Institute / Deutsches Institut für Entwicklungspolitik (DIE) in Bonn.
See also 
- Shaw, John, Sir Hans W. Singer: The Life and Work of a Development Economist, Palgrave MacMillan, 2002 ISBN 0-333-71130-0
- Singer, Hans Wolfgang and John-Ren Chen, Development Economics and Policy: The Conference Volume to Celebrate the 85th Birthday of Professor Sir Hans Singer Palgrave MacMillan, 1998. ISBN 0-312-21041-8
- Hans Singer, EconomyProfessor.com
- Singer archive at the British Library for Development Studies
- UN Chronicle biography
- Profile at The International Institute of Social Studies (ISS)
- Hans Singer’s Debts to Schumpeter and Keynes, John Toye, Cambridge Journal of Economics, 30, 6: 819-833.
- The origins and interpretation of the Prebisch-Singer thesis. John Toye and Richard Toye. History of Political Economy, 35, 3: 437-467