John Bates Clark John Bates Clark was an American economist who lived from 1847-1938. He played an important role in the development of marginal productivity, and had a great influence on the development of economic thought in the United States. Clark was educated at Amherst College and at the University of Heidelberg in Germany. He taught at Carlton College in Northfield, Minnesota from 1875 to 1881. He then moved on to teach at Smith College, Amherst, Johns Hopkins and Columbia from which he retired in 1923. In formulating the Neoclassical theory of the firm, John Bates Clark took over the classical categories of lan