摘要：The last three years have realized significant structural changes in the U.S. agricultural policy environment.These changes include nearly complete planting flexibility and the elimination of target-price-bas ed income s upportfor agricultural producers. Many have questioned the extent to which such policy changes may influence thevariability of agricultural prices. This analysis uses price series dating from 1944 to develop a multivariateframework to evaluate the long-run (inter-season) determinants of endogenous variability for the prices of corn,wheat, and soybeans. An annual measure of price variability is calculated from monthly spot market cash pricesfor each of the three commodities. The generalized method of moments estimation technique is used to model theprice variability measure as a function of several supply and demand variables hypothes ized to be relevant. Severalexplicit policy variables are tested for their effect on output price variability as well as on the variable parameterestimates. Output price variability is found to be sensitive to stocks, demand shocks, yield shocks, input pricevariability, and policy factors. Results vary s omewhat for corn, wheat, and soybeans . Implications for recent farmpolicy changes are offered.
