1924-1932 – Served as an Economist in Wisconsin State Tax Commission.

1932-1938 – Associate Professor of Economics, in University of Cincinnati.

1938-1946 – Director of Tax Research, Department of the Treasury.

1946-1950 – Professor of Economics and Political Science, in University of Chicago.

1950-1952 –  A Member of the Council of Economic Advisers.

1952-1955 – Principal Director of Department of Economic Affairs, United Nations.

1955-1970 – Professor of International Business, in Columbia University.

2000 – He died this year.