This part examines the impact of U.S. agricultural research and education on agricultural productivity. Chapter 10 reviews the principles of productivity index number construction, examines issues in sector and regional productivity measurement, and summarizes new estimates of crop .and livestock productivity for U.S. regions and states. The Delta region has the highest rate of crop livestock, and aggregate multiform productivity increase during 1950-82. The Corn Belt region has a relatively low rate of productivity increase during the study period and it ranked last among the ten regions in livestock productivity increases.