20
great obstacles to development and recently joining the WTO. However, the newest version
of the GTAP 7 database includes an input-output table for the Lao
PDR which might provide
a significant contribution to empirical studies of international trade (Narayann and
Walsmsley, 2008).
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6.0. METHODOLOGY
6.1. Research Framework
The research framework of this study is shown in Figure 6-1. There are two models used in
this study; the GTAP model, and micro-simulation. Firstly, the GTAP model is used to
analyze the impact of trade liberalization on macro-economic variables. Secondly, the results
of the GTAP model (prices and wages) are used in micro-simulation to analyze the impact of
trade liberalization on poverty
13
.
Figure 6-1. The research framework of this study
6.2.GTAP Model and Data Base
Computable equilibrium (CGE) model which called the Global Trade Analysis Project
(GTAP) model was used for our analysis. Computable General Equilibrium (CGE) model
combine economic theory and empirical data to create economic tool for policy analysis such
as changes in tariffs and their effects on whole economic systems .CGE model present the
behavior of economic agents (producers, consumers, and government), sectors (industry,
agriculture, and services) and factors of production (labor, capital and land). CGE model are
of two basic types: a multi-regional computable equilibrium (CEG) model and single
country-CGE model.
The Global Trade Analysis Project (GTAP) model, a multi-region computable equilibrium
(CGE) model, is one of the most popular models for analyzing the impact of trade policies
14
.
There are various advantages to the GTAP model. Firstly, since it is a multi-regional model
of world production and trade, it can take into account the overall trade implications of AFTA
as well as third-party countries. Secondly, it contains a database for different sectors and thus
can explore the trade implications for various sectors of interest
15
.
13
Here, it is important to note that there are other approaches to assessing the impact of trade liberalization on
poverty. The first one is to link the GTAP model with the single country model (with multi-household). The
import and export prices from the GTAP model can be used to shock to the single country model. This approach
can estimate the change in household welfare as a result of trade liberalization. The second approach links the
three models (GTAP model and micro-simulation).The import and export price changes from the GTAP model
can be used to shock into the single country CGE model, then used to shock in the micro-simulation model.
14
The origin of GTAP model is based on ORANI model, a single country CGE model, a first CGE model for
Australian economy (Dixon, Parmenter, Sutton, and Vincent, 1997). GTAP model extended ORANI model for
allowing international trade which introduced a global transportation sector and savings institution.
15
For more details, see Hertel (ed), 1997. A graphic presentation of the GTAP model, with particular emphasis
on the accounting relationships, is given by Brockmeier (1996).
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The GTAP model assumes perfectly competitive markets, where the zero profit condition
holds, and that all the markets are cleared. The regional household allocates expenditure
across three categories: private household, government, and savings. It derives income from
the ‘sale’ of primary factors to the producers, which combine them with domestically
produced and imported intermediate composites to produce final goods. These final goods are
in turn sold both domestically to private households and the Government, and exported to the
rest of the world. Both the Government and private households also import consumer goods
from the rest of the world. A global bank intermediates between global savings and regional
investments by assembling a portfolio of regional investment goods and selling shares in this
portfolio to regional households in order to meet their savings demands. Finally, a global
transport sector assembles regional exports of trade, transport and insurance services and
produces composite goods used to move merchandise trade among regions (Hertel eds,
1997). The flowchart of the GTAP model and production structure in the GTAP model is
illustrated in Figure 6-2.
The latest version of the GTAP database, version 8, is used for this study. To facilitate our
analysis, regions have been aggregated into 21 separate sub-regions (see Appendix 1). All 57
sectors remain as delineated in the GTAP database (Appendix 2).
Figure 6-2. Production structure in the GTAP model
The model closure and free parameters are important factors to influence the simulation result
in CGE model.
Macro closure is important factors to influence the simulation result from
GTAP model. Closure is divided the variables in model to endogenous or exogenous
variables. Endogenous model are determined by the model but exogenous variables are from
outside the model. Macro closure is based on mainly characteristics of economy in the
country which we focus. The closure of GTAP model has various elements such as
population growth, capital accumulation, industrial capacity, technical changes, and policy
variable (tax and subsidies). However, in order to simplify the closure, we use the standard
GTAP closure which called “Neo-classical” closure. This closure assumed that all prices are
flexible; perfect competition (all firm earn zero pure profits); full employment and factor
mobility within regions; investment expenditure is determined by savings rate; tax rates are
fixed.