Tobin, James, 1918–2002, American economist, b. Champaign, Ill., Ph.D. Harvard, 1947. A professor at Yale Univ. from 1950 until his death, he was also an influential member (1961–62) of President Kennedy's Council of Economic Advisers. Tobin's work advanced the significant "portfolio theory," which holds that diversification of interests offers the best possibility of security for investors, and that investments should not always be based on highest rates of return. He also wrote on the process of information exchange between financial markets and "real" markets. Tobin was awarded the Nobel Memorial Prize in Economic Sciences in 1981.