Equilibrium Price Solution of Net Trade Models Using Elasticities

摘要

The report shows a solution procedure which can rapidly calculate equilibrium world prices in a large, complex net trade model. The 'elasticity solution procedure' works for a model in which price elasticities are fairly stable over time and various prices. The model must accept a world price vector and return a residual world net trade vector. The procedure automatically stays in the region of positive prices and quantities. It builds a complete information set of own- and cross-price elasticities to fit the model's behavior. The procedure runs on the IIASA and GOL world agriculture models with sharp improvements in convergence time over Walrasian tatonnement and gradient search, and moderate improvements over Newton's method. The procedure can reconcile inconsistent trade estimates made by country analysts.