1 TRADE RESTRICTIONS AND AFRICA’S EXPORTS By Olayinka Idowu Kareem Department of Economics, University of Ibadan, Ibadan, Nigeria. Matric No.: 113675 E-mail: [email protected]A Paper to be presented at the 2009 Centre for the Studies of African Economies (CSAE) Conference in the University of Oxford, England. February, 2009
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Oceania 233.5 280.3 454.5 405.7 335.4 339.7 450.9 508.7 591.1 668.8 Source: Author’s Compilation from UNCTAD Handbook of Statistics (2007) *This includes Bermuda, Canada, Greenland, Saint Pierre and Miquelon and US. **It includes Israel and Japan. Table 5: Share of Exports by Region (%) Region 1980 1985 1990 1995 2000 2001 2002 2003 2004 2005 2006 World 100.0 100 100 100 100 100 100 100 100 100 100 Developed Countries
This theory evolved with the work of Krugman (1979) and Helpman and Krugman (1985), who
assumed that international trade between countries with similar factors proportion occurs mainly in
differentiated variety on the basis of increasing return to scale (increasing scale economies). These basic
principles cannot fit within the traditional neoclassical models of the Heckscher-Ohlin theory postulating the
development of inter-industry trade between countries as a result of differences in their relative factor
endowments.
Conventional trade theory claims that free trade benefits economies by increasing economies of scale
as they open up wider markets. New trade theory has probed this claim and found that it is true only if certain
strict conditions are met. For example, it requires that industries in which there are increasing returns to scale
expand after trade liberalization. If these industries merely lose sales to foreign competition, then returns to
scale go into reverse.
Similarly, conventional trade theory claims that free trade enhances technological dynamism.
Unfortunately, this is based on the casual assumption that increased competition necessarily increases
dynamism. Thus, it is well established that the relationship between competition and innovation is a lot more
complex than that.
The new trade theory is the theory that based international trade on economies of scale and imperfect
competition. The theory tends to relax the two major assumptions of the no-trade model or the Heckscher-
Ohlin (H-O) model as follows:
1. While the H-O theory assumed constant returns to scale (CRS), international trade can also be based
on increasing returns to scale (IRS).
2. Relaxing the assumption of perfect competition can also lead to new trade theory. About half of the
trade in manufactured goods among industrialized nations is based on product differentiation and
economies of scale, which are not easily reconciled with the H-O factor endowment model. Thus, to
explain intra-industry trade, we need new trade theories.
Underlying the application of the monopolistic competition model to trade is the idea that trade
increases market size. In the industries where there are economies of scale, both the variety of goods that
a country can produce and the scale of its production are constrained by the size of the market. By trading
with each other, and therefore forming an integrated world market that is bigger than any individual
national market, nations are able to loosen the constraints. Each country can specialize in producing a
19
narrower range of products than it would in the absence of trade; yet by buying goods that it does not
make from other countries, each nation can simultaneously increase the variety of goods available to its
consumers. As a result, trade offers an opportunity for mutual gain even when countries do not differ in
their resources or technology.
Suppose for example that there are two countries, each with an annual market for one million
automobiles. By trading with each other, these countries can create combined market of two million
automobiles. In this combined market, more varieties of automobiles can be produced at lower average
costs, than in either market alone (economic of scale).
The monopolistic competition model can be used to show how trade improves the trade-off between
scale and variety that individual nations face. In developing a general model of trade under imperfect
competition, we need to have a representation of consumer choice that treats product differentiation. The
most popular model in the literature is that of Dixit and Stiglitz (1977). There are n varieties of the same
goods with prices Pj
11/
0
niiU Y y d
σ/σ−σ− σ = = σ >1 ∫
, where j = 1, --- , n. The following gives the structure of preferences in the Dixit and
Stiglitz (Ibid) framework:
------------------- (1)
Where 1σ >
Note that equation (1) implies the love for variety.
/ii
y y E npp p
= ==
Where E denotes expenditure. Then:
( )( )
( )
11/
0
11/
1
1/ 1
/
/ (2)
niY y d
ny
nE np
nE p
σ/σ−σ− σ
σ/σ−σ− σ
σ/σ−
σ−
=
=
=
= − − − −
∫
Clearly, equation (2) implies that the higher the number of varieties n , the higher the utility U (hence, the
love for variety).
The Utility Maximization problem is:
0
0. .
i
ni i
y
s t p y E
MaxY≥
≤∫
The langrangian for the problem takes the form:
20
11/
0
n nii i il y d p y E
σ/σ−σ− σ
0
= −λ − ∫ ∫
The necessary and sufficient FOC’s for this problem are
For variety i : ( )( )1) 1
1/ 1/
01) 1/
n
i i i iy d y p(σ/σ− −
σ− σ (σ− σ)−1 (σ/σ − σ− σ = λ ∫
For variety i : ( )( )1) 1
1/ 1/
01) 1/
n
i i j jy d y p(σ/σ− −
σ− σ (σ− σ)−1 (σ/σ − σ− σ = λ ∫
Taking the ratio of the FOC’s we get:
1/
i i i i
j j j j
y p y py p y p
− σ −σ
= ⇔ =
(3)
Or, using the law of logarithms,
ln ln (4)
ln( ) ln( ) ln( ) ln( ) (5)
i i
j j
i j i j
y py p
y y p p
= −σ − − − −
⇔ − = −σ − − − − −
Equation (3) represents the relative demand for any two varieties as a function of relative prices and σ . We
can now be more explicit on the parameterσ :
(a). | σ | is the (constant) elasticity of substitution between varieties – see equation (4)
(b). | σ | is also the constant price elasticity of demand – see equation (5).
Now we can manipulate equation (3) in order to get an expression for :
yi= yi (pi, E, p)
Multiply both side by pi,
i i i
j j
p y py p
1−σ
−σ=
to get:
Integrate between 0 and n
0 0
n n
i i i i i
j i
p y d p d
y p
1−σ
−σ=∫ ∫
Using the budget constraint, we can conveniently rewrite this expression as follow:
21
0
0
/
(6)
n
i ii
j
jj n
i i
p dE y
p
py E
p d
1−σ
−σ
−σ
1−σ
=
= − − − − −
∫
∫
Now, define the price index as a CES aggregate of prices:
1/1
0
n
i ip p d−σ
1−σ = ∫ ------------ (7)
Equation (6) then becomes:
( ) 1, , ji j j
py y p E p E
p
−σ
−σ= = ---------- (8)
Which is the demand for variety j.
3.1 The Model
The model for this thesis is adapted from the empirical work of Mayer and Zignago (2005) that
modeled market access in global and regional trade through a border-effect methodology. The modification
that our thesis has done to the work of Mayer and Zignago (2005) is by including regional trade agreements,
colonial affiliation and language. The theoretical underpinning the gravity type will occur in almost every
trade model with full specialization, as shown by Evenett and Keller (2003). The theoretical framework for
this model is derived from the new trade theory above that made provision for economic of scale and
imperfect market. Bergstrand (1990)1
Tinbergan (1962), Poyhonen (1963) and Linnemann (1966) were the set of researchers that first
applied gravity model to the analysis of global trade flows. The name of the model was derived from its
passing similarity to Newtonian physics, which indicates that large economic entities such as countries or
cities are said to exert pulling power on people (Migration Model) or their goods (trade models) or capital
(FDI model). The simplest form of international trade gravity model assumes that the volume of trade
between any two trading partners is an increasing function of their national incomes and populations, and a
decreasing function of the distance between them. In the model it is common to use the dummy variables to
capture geographical effects (such as signaling whether the two countries share a border, or if a country has
provides a description of the link between gravity equation and
bilateral trade patterns in a monopolistic competition framework of the new trade theory.
1 See the appendix for the specification of Bergstrand equations that gave the basis for the use of gravity model in this thesis.
22
access to the sea), cultural and historical similarities (such as if two countries share a language or were linked
by past colonial ties), regional integration (such as belonging to a free trade agreement or sharing a common
currency), as well as other macroeconomic policy variables (such as biliateral exchange rate volatility).
Anderson (1979), Bergstrand (1985) and Helpman and Krugman (1985) have derived gravity equations from
trade models based on product differentiation and increasing returns to scale. Linnemann and Verbruggen
(1991) have explicitly studied the impact of tariffs on bilateral trade patterns using a gravity model
framework. However, it was Estevadeordal and Robertson (2002) that explicitly studied the incorporation of
preferential tariff rates in a gravity model.
The monopolistic competition model of new trade theory provides the theoretical foundations to the
gravity model (Helpman, 1987 and Bergstrand, 1989). Here, the product differentiation by country of origin
approach is replaced by product differentiation among producing firms, while the empirical success of the
gravity model is considered to be supportive of the monopolistic competition explanation of intra-industry
trade.
Assume that the consumers in country i have a two-level utility function where the upper level is a
Cobb-Douglas with expenditure parameter ui, which gives rise to a fixed expenditure share out of the
income, yi
( )1
1
1 1
N jN
i ij ijj h
U a c
σσσ
σ−−
= =
= ∑ ∑
. The lower level utility function on the other hand is a constant elasticity of substitution (CES)
aggregate of differentiated varieties produced in the considered industry, with σ representing an inverse index
of product differentiation.
-------------------------------- (9)
The CES structure usually indicates the love for variety, based on the fact that the consumers are
willing to consume all the available varieties. Our study shall deal with a situation where the consumers have
different preferences over varieties depending on bias. The consumers’ preference parameter in country i for
varieties produced in j is denoted aij
ijτ
.
Given the fact that most of these varieties are produced in foreign countries, there is need to model
trade cost, that ought to be ad valorem, and incurred by the consumer when the good is transported from
country j to country i . The delivered price pij faced by consumers in i for products from j is therefore the
product of the mill price (cost of production) pj and the trade cost. The trade costs include all transaction
costs associated with the movement of goods across the space and natural borders. The demand for a
representative variety produced in j is denoted as cij,
1 1 1 1 (10)ij j ij ij j ij j ij i i iM P C a P Y Pσ σ σ ση η τ µ− − − −= =
which the demand function derived from this system
gives the bilateral total imports by country i from country j for a given industry.
where ( ) ( )σσκ
σκ
σκκκ τη
−−−−∑=1/1111
iii PaP is the “price index” in each location.
23
From equation (2), one could see that trade costs influence demand when there is a high elasticity of
substitution, σ . Based on Head and Mayer (2000), we take the ratio of mij over mii
1−σµ iii py
, country i’s imports from
itself, the term then drops and we are left with relative numbers of firms, relative preferences, and
relative costs in country i and j. 111 −−−
=
σσσσ
ii
ij
i
j
ii
ij
i
j
ii
ij
TT
PP
aa
nn
mm
(11)
In order to estimate equation (3), the model must be specified fully by adopting the supply side
features of the monopolistic competition model. Hence, the firms producing qj in country j employ lj
jj rqFl +=
workers in an IRS production function , where F is a fixed (labour) costs, and r is the inverse
productivity of firms. The profits are ( )jjjjj rqFwqp +−= , where wj
( )r
Fq j1−
=σ
is the wage rate in country j. Thus,
equilibrium output of each representative firm is, . We assume an identical technology that is
Nqq jj 1, =≡ ν and Vj is the value of production for the considered industry in country j, υj=qpjnj
j j i
i i j
n pn p
υυ
=
, from
equation (3):
------------------------ (12)
Also, the functional forms of trade cost )( ijτ and preferences (aij) have to be specified in order to get
an estimable equation. The trade costs are function of distance (dij, which proxies for transport cost) and
“border-related costs” that consist of tariffs and non-tariffs barriers (NTBs) (these include, quantitative
restrictions, administrative burden, sanitary measures, etc). The ad valorem equivalent of all border-related
costs brcij
( )1ij ij ijd brcδτ ≡ +
is given as:
------------------------------ (13)
We shall allow the border related costs to be flexible in this study, since our aim is to assess a
possible North-South divide in market access; we then need to allow for different levels of broadly defined
protection in each (North-South and South-South) direction. Also, of importance is the issue of effect of
regionalism, which we are going to control in the assessment of North markets’ access by Southern exporters.
Further, we observed some of the actual protection that is taking place between importing and exporting
countries (tariffs and NTBs). We shall include measures of market access initiatives in order to determine
the extent to which these initiatives would impact on African exports.
Generally, we assume the following structure for border-related costs that vary across country pair
and depend on the direction of the flow of a given pair:
( )( )( )1 1 1 exp ijij ij ij ij ij ijbrc t ntb E RTA NS SNη θ ϑ ϕ + ≡ + + + + + -------------- (14)
24
From this specification, tij denotes the ad valorem bilateral tariffs, ntbij is a frequency index of NTBs.
Trade Agreements, RTAij ( )ji ≠ is a dummy variable set equal to 1 when and j belongs to a regional
integration agreement. We expect θ > 0 to be the lowest of those parameters, which will be true if all
national borders impose transaction costs, with the minimum burden of those costs being between RTA
members.
The preferences have a random component eij
β
, and a systemic preference component for goods
produced in the home country, . The home bias is assumed to be mitigated by the share of a common
language.
( )( )expij ij ij ij ij ija e L E NS SNβ λ ≡ − − + + -------------------- (15)
Lij is set equal to 1 when two different countries share the same language. When Lij
β
switches from 0 to 1,
home bias changes from to β - λ .
Therefore, based on all the above, we obtain an estimable equation with respect to Africa’s trade
relations with her trading partners from the monopolistic competitive equation of Krugman (1980) with home
bias:
( )[ ] ( ) ( ) ( ) ( ) ( )
[ ]1 1
1 1 1 1 1 1
( 1)
ij j jij ij
ii i i
ijij ij
ii
m PIn In In In t In ntb
m P
dIn RTA
d
υσ β η σ σ σ σ δ
υ
σ θ η
= − − + + − − − + − − + − −
− − − +∈
----------- (16)
where ( )( )1ij ij iie eσ∈ = − −
( )[ ]( )ηβσ +−− 1 is the constant of equation (16) and it gives the border effect of the international trade for
countries that belong to the same group, the South for instance. This includes both the level of protection of
the importing country (η ) and the home bias of consumer ( β ). The coefficient RTA measures the effect that
the regional and multilateral trade agreements have on African exports.
3.2 Apriori Expectation
Theoretically, we expect an inverse relationship between relative price and Africa’s exports, due to
the problem of imported inflation that might arise in the economies of Africa’s trading partners. Relative
output is expected to have a direct relationship with Africa’s exports, that is, as output increases; there will be
more to export. Tariffs and non-tariffs are expected to have inverse relationship with Africa’s exports. This
means that as more market conditions are imposed on Africa’s exports there will be restriction in the access
25
of Africa’s exports and if eventually the exports get into the trading partners market, it cannot compete
favourably with similar products.
Same colonial affiliation is expected to enhance trade theoretically, that is, countries of the same
colonial affiliation tend to trade more with themselves. Language is a barrier to trade if the trading partners
did not speak similar language. Distance is another inhibiting factor to trade, that is the higher the distance,
the lower the trade. Involvement in trade agreements is expected to boost trade among trading partners.
3.3 Estimation Issues
The main reason for preferring panel data analysis is that the cross-section specification is very likely
to suffer from omitted bias because of the unobserved county specific effects, outlines, model uncertainty and
it completely neglects the temporal aspects (and dynamics) of foreign trade.
The generalized method of movements is adopted as the estimation technique in this thesis because it has the
potential to correct for endogeneity and heteroscedascity problems that may arise from the use of other panel
data estimation techniques. According to Greene (2004), GMM provides an estimation framework that
possesses a method of formulating models and implied estimators without making strong distribution
assumptions.
Endogeneity of the right-hand regressors is a serious problem to the ordinary least square (OLS)
estimators, because it will lead to omission of variables, measurement error, self-selection and sample
selectivity. Thus, these problems cause inconsistency in the OLS estimates and thus could be corrected by the
use of any instrumental variables estimators (Baltagi, 2001). The GMM estimator is asymptotically efficient
with an increasing set of instruments as the sample size grows attains the semi-parametric efficiency band of
the model (Conley, 1991)
3.4 Estimation Techniques
This study makes use of generalized method of moment panel data analytical methods with the test of
the panel data properties and panel granger causality. These methods allow us to estimate our regression
equations for the whole of Africa and the sub-groups.
The reason for the use of panel data technique in the gravity model is based on the several benefits of
the technique as identified by Hsiao (1985, 1986), Klevmarken (1989) and Solon (1989). It could be used to
control for individual heterogeneity, it provides more informative data, more variability, less collinearity
among the chosen variables, more degree of freedom and more efficiency. Also, panel data technique is a
better option when one intends to study the dynamics of adjustment and duration of economic states like
poverty and employment, and if these panels are long enough, they can shed light on the speed of
adjustments to economic policy changes. Panels are necessary for the estimation of inter-temporal relations,
life-cycle and intergenerational model and they can easily relate individual’s experiences and behaviour at
26
another point in time. They are better able to identify and measure effects that are simply not detectable in
cross-section or time-series data, such as in ordinary least square (OLS) method.
The basic class of specification of these models is given as:
( ) ittiitit XfY ∈+++= γδβ, (1)
This leading case involves a linear conditional mean specification, so that we have:
ittiititit XY ∈++++= γδβα (2)
Where Yit stands for the dependent variable, Xit it∈ is a K – vector of regressors and are the error terms for i
= 1, 2, …, M cross-sectional units observed for dated periods t = 1, 2, …, T. The α represents the constant
of the model, while the iδ and tγ represent the fixed and random effects, respectively. Identification
obviously requires that the β coefficients have restrictions placed upon them. They may be divided into sets
of common (cross-section and periods), cross-section specific, and period specific regressor parameters.
This panel estimation technique will enable us to estimate panel equations using linear or non-linear
squares or instrumental variables (system of equations), with correction for the fixed or random effects in
both the cross-section and period dimensions and in addition, the generalized method of moment (GMM) will
be used to estimate the specification with various system weighting matrices. It should be noted that apart
from the above basis for panel data analysis, panel equations allow us to specify equations in general form
and also permits specification of non-linear coefficients mean equations with additive effects. Panel
equations do not automatically allow for β coefficients that vary across-sections or period, but one may
create interaction variables that permit such variation.
Table 6: Variable Definitions and Sources Variable Description Source Pj/Pi This is the ratio of prices between Africa
and her trading partners (measured by CPI and also known as relative prices)
= Ratio of Prices (Rprices)
IFS
Vj/Vi The ratio of output/production between Africa and the selected trade partners (Measured by their GDP)
= Ratio of Outputs (Routputs)
IFS
Dis = distance The distance from the capital of country ί (trade partners) to the capital of country j (selected African countries). This is a measure of transport cost.
www.timeanddate.com
tij Weighted average of Ad-valorem tariffs = Tariffs UNCTAD (WITS) Lij Language of the trading countries = Language www.wikipedia.org Colij The Colonial link between country ί and
country j = Colonial www.wikipedia.org
NTB = Non-tariff barriers Non-tariff barriers measured by the number of times (known as coverage ratio) Quad countries, China and India use these to distort trade.
WTO (WITS)
RTA = regional Trade Agreements
Regional trade agreement is given the value of one when both partners belong to this arrangement, otherwise zero.
Note: The Figures in parentheses are the t-statistic. The superscripts c, b, a indicate 1%, 5% and 10% level of significant, respectively.
37
5. Conclusion
This study has shown in details the various trade restrictions that Africa’s exports are encountering in
the course of gaining access to the markets of the selected trading partners in both the North and South
countries. We have also shown empirically using both descriptive analysis and econometrics method, the
effect of these trade restrictions on Africa’s export products access to both industrialized and developing
markets. Furthermore, the directions of causality between trade restrictions and market access of products
relevant and of importance to African countries have been established.
Thus, at this juncture, it is important to note that all the objective of this study has been adequately
achieved and accomplished, that is, we have shown the effect of market access conditions on Africa’s exports
in the developed country (USA) and developing country (India).
Therefore, we conclude that African exports have not been gaining access to both industrialized and
developing countries not only because of the trade restrictions imposed on their products, but due to the fact
that Africa has low and inadequate production capacity that will enable her to meet up with the market access
allowed to her products despite the potentiality of her output gaining access to these trading partners markets.
We also conclude that products of relevance to African countries are confronted with higher trade restrictions
mostly in the developing countries than in the developed countries. This means that there are more market
access conditions in South-South trade than North-South trade, which confirm the results of Mayer and
Zignago (2005), and Hammouda, Karingi and Perez (2005).
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