As part of its research program during the last 4 years, the Agricultural Estimates Division, AMS, has conducted extensive studies on objective yield forecasting methods for several important field crops. Some results of these studies on cotton in the South and on soybeans in the North Central States have been reported in earlier issues. Results of the studies on corn reported in this paper are based on data for 4 years in the South and for 2 years in the North Central States, together with data from a project that has been conducted in cooperation with Iowa State College for several years.