2003-2007: Director, Giannini Foundation of Agricultural Economics
1999-Present: Robinson Chair, Agricultural and Resource Economics, University of California at Berkeley; Director, Center for Sustainable Resource Development.
1994-2000: Chair, Agricultural and Resource Economics, University of California at Berkeley; Director, Center for Sustainable Resource Development.
1989-1994: Vice Chairman, Agricultural and Resource Economics, University of California at Berkeley.
1987-Present: Professor of Agricultural and Resource Economics and Agricultural and Resource Economist in the Agricultural Experiment Station, University of California at Berkeley.
1983-1987: Associate Professor of Agricultural and Resource Economics and Associate Agricultural and Resource Economist in the Agricultural Experiment Station, University of California at Berkeley.
1979-1983: Assistant Professor of Agricultural and Resource Economics and Assistant Agricultural and Resource Economist in the Agricultural Experiment Station, University of California at Berkeley.
1977-1978: Postgraduate Research Agricultural Economist, University of California at Berkeley.
1977-1978: Lecturer (part time), School of Business, San Francisco State University (subjects:Managerial Economics, Operation Management), 1976-1978; Lecturer (part time), School of Business, Lincoln University, San Francisco (subjects: Computer Programming, International Trade).
1973-1976: Research Assistant, University of California at Berkeley.
1971-1973: Teaching Assistant, Department of Economics, Tel Aviv University, Israel (subject: Econometrics).
1968-1973: Programmer and Systems Analyst, Koor Computers, Tel Aviv, Israel.