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CGEBox - a flexible and modular toolkit for CGE modelling with a GUI

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    CGEBOX provides a flexible, extendable and modular code basis for CGE modeling in GAMS drawing on the GTAP data base, combined with a powerful user interface based on GGIG (GAMS Graphical User Interface Generator). The code and user interface is open source and can be downloaded from the internet (see Documentation section).

    As the model draws on GTAP data base, an appropriate GTAP license is required or the older, by now for-free versions of the data base can be used. The system aims at complex applications, including solving very large models, but the user interface and options to visualize and analyze results in tables, maps and graphs render it also useful for class-room use.

    CGEBox offers a truthful replica of the GTAP Standard model. Using either switches on the interface or by changing the parameterization or the data base underlying the model, different additional features or variants can be derived:

    • A recursive-dynamic long term version G-RDEM by Roberto Roson and Wolfgang Britz
    • A single region model with fixed import prices and FOB prices driving bi-lateral export demand
    • A partial equilibrium set-up where only one or some commodity markets clear and the remaining cross-prices and input demands are fixed and accounts are not closed
    • A two-level CET representation of distribution of supply to domestic use or exports, respectively to different export destination, mimicking the Armington CES representation on the demand side
    • Non-diagonal make matrices where one sector can produce several outputs or one output can be produced by several sectors, with matching CET/CES nests
    • Different closures for final, government, investment demand and foreign savings, a version with endogenous exchange rates
    • Support for flexible nestings in the production function, for factor supply and CES-subnests under final demand, based on set-definitions in GAMS. Does not require additional coding of equations and variables
    • Choice between CDE, CD, LES and AIDADS as functional forms in final demand. The AIDADS system is estimated to capture structural changes in demand under larger income changes, relevant for G-RDEM

    Modules

    CGEBox already implements different modules which replicate variants of the GTAP model or provide new extensions which can be combined in applications:

    • GTAP-AGR: intermediate demand nests for feed use in livestock production and for primary agricultural products into food processing sector; a split-up into an agricultural and non-agricultural households; CET-driven factor supply between agriculture and non-agriculture and inside the agricultural sector. Note that water can be aded as primary factor when using the GTAP-WATER data base.
    • GTAP-E: Multi-stage nesting for energy-capital composite in production and demand nests for energy use. CO2 emissions. The GTAP-WATER water data base supported by the data driver also cover additional sector detail in electricity production from the GTAP-Power data base.
    • GTAP-AEZ: Sub-regional land supply linked with CES/CET structures, support to both the 2007 and 2011 releases of the landuse data base.
    • myGTAP: Support for several private households, replacement of regional household approach by separate accounts for the different agents. Can be used to define for instance a household drawing income from factor use in agricultural and non-agricultural activities.
    • GTAP-Melitz: Love of varieties linked to endogenous number of firms for each sector and operating on each bi-lateral trade link, increasing return-to-scale based on fixed costs, monopolistic power, separate technology nests for fixed and variable costs. Can be simplifited to a Krugmann model. Which sectors are covered can be chosen by the user. The module is developed and maintained by Yaghoob Jafari and Wolfgang Britz.
    • GTAP-MRIO: Bi-lateral import demand dis-aggregated to total intermediate demand and each final demand agent, split factors courtesy of the OECD secretariate in Paris as used in the OECD's METRO model. Which sectors are covered can be chosen by the user.
    • Tariff lines: A prototype module allows to dis-aggregate selected bi-lateral trade flows to the tariff line level using an additional CES-CET structure. It supports multiple bi-lateral Tariff-Rate-Quotas in combination with a MCP solver.
    • GTAP-NUTS2: Dis-aggregation of national production and factor markets to sub-regions. Currently, data area available for about 280 NUTS2 regions for European countries.
    • GTAP-TIVA: Post model generation of a global Leontief-inverse to derive Trade-In-Value added indicators and to attributes global changes in CO2 / non-CO2 emissions to regional final demand.
    • ALTERTAX: Post-model generation of a global SAM to provide an updated benchmark.
    • G-RDEM: A module for generation of long-term baselines which features (1) an AIDADS demand system with non-linear Engel curves, (2) debt accumulation and serving from foreign savings, (3) sector specific productivity growth, (4) macro-economic saving rates adjust to population and GDP dynamic, (5) dynamics IO-Coefficients and factor shares. G-RDEM uses as a default the GDP and population projection at single country level for SSP 1-5 form the IIASSA SSP data base which can be combined with climate change impacts on crop yields from various Global Circulation Models and Gridded Crop Growth models for different RCPs provided by EU-CLIM project.

    These extensions can be generally freely combined. Additionally, the first stage Armington nest can be aggregated across agents, or alternatively, all intermediate demand can be aggregated.

    CGEBox is jointly developed and by Wolfgang Britz, Dominique van der Mensbrugghe, Yaghoob Jafari and Roberto Roson.

    May 2018 -\ (matches rev. 1385 of https://svn1.agp.uni-bonn.de/svn/Gtap8InGams)