The relative importance of key state-level outcomes upon U.S. national corn and soybean production was examined using correlated component regression, a recently developed regression technique for application to multicollinear and sparse data sets. Standardized coefficients were used to rank the states’ relative importance. A Herfindahl-Hirschman Index was used to measure the degree of concentration among the top ranked states. The empirical analysis looked at two time periods: a pre-Genetic Modification (1975–1995) and a post-Genetic Modification (1996–2017) period. The results indicate that U.S. corn production is becoming less geographically concentrated in terms of state-level importance while the opposite holds true for soybean production.

Geographic concentration in U.S. hog production from 1974-96 is investigated using a measure based on Theil's entropy index. For the U.S. as a whole, geographic concentration is occurring at a slow rate, both for hog farms and hog numbers. However, for particular states, primarily in the new Southern Atlantic production region, concentration is high and increasing at a rapid pace. Concentration was increasing for the 23-year period for 16 out of the 20 states in the analysis. Results indicate that geographic concentration by augmentation is occurring to the greatest degree in Arkansas, Missouri, North Carolina, Oklahoma, and Pennsylvania.