Introduction and overview

The Global Trade Analysis Project (GTAP) benchmark data and parameters are specified for 37 commodities and 24 regions. Due to the size of this data set, an aggregated version of the data base and parameters will be desired for most GTAP simulations. The precise dimensions of each aggregation will depend on the problem at hand. Experienced users tend to favor strategic aggregations that allow them to focus on key sectors and regions of interest. This makes the job of sorting through the simulation results less daunting. For teaching purposes, we usually begin with the three-region, three-commodity (3×3) aggregation referred to in Chapters 2 and 4. Section II introduces you to the GTAP aggregation facility that created this 3×3 data set. We will also examine some of the key value flows, as well as the full parameter file. In section III, local behavior of the 3×3 model will be examined through the use of general equilibrium demand elasticities. This offers a valuable summary of the interaction between theory, data, and parameters in the model.

Aggregation of the GTAP data

The user specifies the desired aggregation of the GTAP data base by filling in a template file. This involves defining names for the aggregated commodities and associating them with disaggregate GTAP commodity categories, then doing the same for regions.