Sargent, Thomas John, 1943–, American economist, b. Pasadena, Calif., Ph.D. Harvard (1968). He has been on the faculty at the Univ. of Pennsylvania (1970–71), Univ. of Minnesota (1971–87), Univ. of Chicago (1991–98), Stanford (1998–2002), and New York Univ. (2002–), and also has been a research associate with the National Bureau of Economic Research (1970–73, 1979–) and a senior fellow at the Hoover Institution (1987–). Sargent developed and used econometric models to examine historical macroeconomic data and show how long-term economic policy changes and expectations concerning their effects impact the economy, thus providing insights into the effects of government economic policy. A proponent of rational expectations theory early in his career, he has since also been critical of aspects of the theory. Sargent has studied historical hyperinflation, persistent high unemployment in modern Europe, and Federal Reserve policies since World War II and their effects on the U.S. economy. In 2011 he shared the Nobel Memorial Prize in Economic Sciences with Christopher Sims for their separate empirical research on cause and effect in the macroeconomy.