CGEBox: A Flexible, Modular and Extendable Framework for CGE Analysis in GAMS

We present CGEBox, an open-source and open-access framework for regional and global Computable General Equilibrium analysis realized in the General Algebraic Modeling System (GAMS) software. It flexibly depicts different nestings in production and factor supply, supports different functional forms for demand and choices in modeling international trade sectors (Armington, Armington plus Constant Elasticity of Transformation to distribute supply, Melitz and Krugman model). Either a regional household approach or separate accounts for government and potentially multiple private households with related closures are available. Supply and factor markets can be dis-aggregated to sub-regions and an implementation for GTAP-AEZ is available. We compare the layout of different well-known global and single country CGE models and discuss to what extent our flexible framework can replicate these layouts. In a structural sensitivity analysis, we compare major results under multi-lateral trade liberalization and endowment changes in one country for different model configurations. These reflect important structural differences between the chosen examples as well as additional features such as the Melitz model or endogenous capital stocks driven by investments in a comparative-static setting. We find relative limited differences in global and regional welfare between models based on the Armington assumption, even if other features differ such as closures, nestings or functional form in demand. A discussion on further joint development of such a framework leads to our summary and conclusions.