Tjalling Charles Koopmans ( born August 28, 1910 in 's- Graveland, today Wijdemeren, † 26 February 1985 in New Haven, Connecticut) was an American economist and physicist Dutch descent. In 1975 he received together with Leonid Kantorovich Vitalyevich the Prize in Economic Sciences the Bank of Sweden in memory of Alfred Nobel for their contribution to the theory of optimal resource use.
Koopmans was the son of a teacher couple and went to school in Hilversum. From 1927 he studied mathematics and physics at the University of Utrecht, with the conclusion of 1932. During his studies he became interested in economics and studied with Jan Tinbergen in Amsterdam and Ragnar Frisch in Oslo. In 1936 he received his doctorate at the University of Leiden with the work Linear regression analysis in economics. From 1936 he was a few years colleague of Tinbergen at the Netherlands School of Economics in Rotterdam and then also. Tinbergen with the League of Nations in Geneva, where he worked on the modeling of business cycles After the occupation of France and the Netherlands by the Nazis, he went to the United States to exile. He conducted research at Princeton (1940 /41), was then at the Mutual Life Insurance Company in Philadelphia and at the British merchant ship mission in Washington, DC, where he worked on the optimization of shipping routes between the U.S. and England. He published his results in a paper in 1944 (Exchange ratio in between cargos on different routes, first published in 1970), who founded the activity analysis in operations research. His works from this period made him also next to Kantorovich and Dantzig George one of the pioneers of linear programming. In 1944, he joined the Cowles Commission for Research in Economics at the University of Chicago in 1955 and he went to Yale University, where he was Alfred Cowles Professor of Economics, and in 1980 went into retirement.
He was married since 1936 with the economist Truus When Willingen, with whom he had two daughters and a son. In 1946 he took on U.S. citizenship. He was a member of the National Academy of Sciences and the American Academy of Arts and Sciences. Koopmans was president of the American Economics Association and the Econometric Society. In 1962 he was invited speaker at the International Congress of Mathematicians in Stockholm (Utility and time: on axiomatic discussion with Richard Williamson ).