Mr. Niskanen (pronounced nis-CAN-en) had a long career as an economist, both in and out of government. He taught at the University of California at both Berkeley and Los Angeles, worked as a defense analyst at the RAND Corporation and held prominent positions at the Office of Management and Budget, where he was assistant director, and at the Defense Department, where he was the director of special studies for the secretary of defense. Born on March 13, 1933, in Bend, Ore., he earned a bachelor’s degree from Harvard and a Ph.D. in economics from the University of Chicago, where he studied under Milton Friedman, the free-marketeer and Nobel laureate. Mr. Niskanen, who lived in Washington, is survived by his wife, Kathryn Washburn, and three daughters; Lia Niskanen of Brooklyn, Pamela Niskanen of West Winfield, N.Y., and Jaime Brunetti of Berkeley, Calif.