[2] De Haas started his working life in 1914 as special agent for the California Commission of Immigration.
[1] His teaching assignment was "business theory, in particular the technique of trade, account science".
[3] In 1921, De Haas left for the United States, where he had received US nationality in 1917.
[1] He was appointed chairman of the Economic Division of the Netherlands Post-war Planning Committee here in 1942.
De Haas married Hazel Gertrude Carus on December 25, 1914, who died on April 12, 1922.