Given the good performance of LAC economies during the first decade of the twenty first century and the fact that many of these countries have export-oriented economies based on commodities, this study examines the effects of commodity exports on countries’ per capita economic growth rates from 1990 to 2010 and during the commodity boom from 2000 to 2010 using a panel data analysis. First, we apply a chow breakpoint test to the three commodity price series shown in Fig. 1 to confirm 2000–2010 as the boom period. The results, shown in “Appendix”, reject the null hypothesis for the three series, supporting the definition of the boom period as 2000–2010.
Next, we develop three estimation models centered on the literature review. The models are based on the relationship between the economic growth and measures of export composition, following Al-Marhubi (2000). The first model contains only the classical variables of the ELG model and trade partner growth. The second model includes interaction variables for the boom period and for the LAC countries during the boom. Third, we estimate five equations where we include individually each of the four commodity exports and manufactured exports, with interactions for the boom and the boom in LAC countries. The base model is shown in Eq. 1 and is similar to Al-Marhubi (2000).
$$y_{it} = \alpha + \sum\limits_{k = 1}^{n} {\beta_{k} } x_{kit} + \sum\limits_{j = 1}^{m} {\gamma_{j} } z_{jit} + \varepsilon_{it} ,$$
(1)
where \(y_{it}\) is the GDP per capita growth for country i in year t,
\(x_{kit}\) is the control variables k for country i in year t and \(z_{jit}\) is the j export variables. The control variables are the initial level of GDP per capita in each country (Y
i0
); labor (l
it
) and capital (k
it
) (following the neoclassical growth model); and aggregate exports (ax
it
) and a weighted average growth of country i’s trade partners (tp
it
). As a proxy for the natural logarithm of labor, we utilize the hypothesis that hours worked are stationary around a time trend, as in DeJong and Whiteman (1991), Dreger and Herzer (2013), and Leybourne (1995). Thus, in this model, the effect of labor is incorporated as a constant \(\beta_{1}\). Then the model can be written as Eq. 2.
$$y_{it} = \alpha + \beta_{0} Y_{i0 } + \beta_{1} + \beta_{2} k_{it} + \beta_{3} ax_{it} + \beta_{4} tp_{it} + \mathop \sum \limits_{k = - 1}^{1} \gamma_{k} z_{it} + \varepsilon_{it} ,$$
(2)
where β
0 is a negative parameter and the other β’s are positive parameters.
As exports may have an endogeneity problem with the dependent variable, the lead and lag differences of export growth are added to the equation, so their coefficients \(\gamma_{k}\) account for serial correlation and endogeneity (Herzer and Vollmer 2012).
Our second model includes the impact of the boom period on all countries in our study and on the LAC countries, and is shown in Eq. 3.
$$\begin{aligned} y_{it} &= \alpha + \beta_{0} Y_{i,o} + \beta_{1} + \beta_{2} k_{it} + \beta_{3} ax_{it} + \beta_{4} tp_{it} + \beta_{5} {\text{Boom}}D_{t} + \beta_{6} {\text{Lac}}D_{i} \cdot {\text{Boom}}D_{t}\hfill \\ &\quad + \left( {\beta_{7} k_{it} + \beta_{8} x_{it} + \beta_{9} tp_{it} } \right) \cdot {\text{Boom}}D_{t} + \left( {\beta_{10} k_{it} + \beta_{11} x_{it} + \beta_{12} tp_{it} } \right)\hfill \\ &\quad \times {\text{Lac}}D_{i} \cdot {\text{Boom}}D_{t} + \mathop \sum \limits_{k = - 1}^{1} \gamma_{k} \Delta x_{it} + \varepsilon_{it} . \hfill \\ \end{aligned}$$
(3)
BoomD
t
is a dummy variable that takes on a value of 1 from 2000 to 2010 and 0 at any other time; and \({\text{Lac}}D_{i} \cdot {\text{Boom}}D_{t}\) is a dummy variable that takes on a value of 1 only for LAC countries during the commodity boom period (2000–2010) and a value of 0 for non-LAC countries. The interaction terms \(\left( {\beta_{7} k_{it} + \beta_{8} ax_{it} + \beta_{9} tp_{it} } \right) \cdot {\text{Boom}}D_{t}\) and \(\left( {\beta_{10} k_{it} + \beta_{11} ax_{it} + \beta_{12} tp_{it} } \right) \cdot {\text{Lac}}D_{i} \cdot {\text{Boom}}D_{t}\) are included to assess the channel through which the export boom affected growth for the entire group of countries, as well as for LAC countries.
In our third set of models, where we test for the effect of specific types of exports on growth, we run separate analyses for four commodity groups (agricultural raw materials exports, ore and minerals exports, food exports, and fuel exports) and for manufactured exports, all measured as a percentage of merchandise exports for each country. This disaggregation is taken from the classification by the World Bank in the WDI database. In these analyses, we include \({\text{Boom}}D_{t}\) and \({\text{Lac}}D_{i} \cdot {\text{Boom}}D_{t}\) variables as well as three new variables to include the impact of each specific export type for each country on the GDP per capita growth. CommD
ij
is a variable where \(j\) stands for agriculture exports, food exports, fuel exports, ore and mineral exports or manufactured exports. \({\text{Comm}}D_{ji} \cdot {\text{Boom}}D_{t}\) represents exports of each export category \(j\) during the boom period for each country, while \({\text{Lac}}D_{i} \cdot {\text{Comm}}D_{ji} \cdot {\text{Boom}}_{t}\) represents exports of each export category during the boom period only for LAC countries. This model is presented in the Eq. 4.
$$\begin{aligned} y_{it} &= \alpha + \beta_{0} Y_{i,o} + \beta_{1} + \beta_{2} k_{it} + \beta_{3} ax_{it} + \beta_{4} tp_{it} + \beta_{5} {\text{Boom}}D_{t} + \beta_{6} {\text{Lac}}D_{i} \cdot {\text{Boom}}D_{t} \hfill \\ &\quad + \left( {\beta_{7} k_{it} + \beta_{8} ax_{it} + \beta_{9} tp_{it} } \right) \cdot {\text{Boom}}D_{t} + \left( {\beta_{10} k_{it} + \beta_{11} ax_{it} + \beta_{12} tp_{it} } \right) \cdot {\text{Lac}}D_{i} \cdot {\text{Boom}}D_{t} \hfill \\ &\quad + \beta_{15j} \cdot {\text{Comm}}D_{ji} + \beta_{16j} \cdot {\text{Comm}}D_{ji} \cdot {\text{Boom}}D_{t} \hfill \\ &\quad + \beta_{17j} \cdot {\text{Comm}}D_{ji} \cdot {\text{Lac}}D_{i} \cdot {\text{Boom}}_{t} + \mathop \sum \limits_{k = - 1}^{1} \gamma_{k} \Delta ax_{it} + \varepsilon_{it} . \hfill \\ \end{aligned}$$
(4)
Most of the data were obtained from the World Bank’s World Development Indicators (WDI) (World Bank 2012) for the period 1990–2010 for 97 countries, 14 of which are LAC countries. The WDI variables for each country are real GDP per capita growth (annual %); real GDP per capita in 1990; gross capital formation (annual % growth); exports of goods and services (annual % growth); and agricultural raw materials exports, food exports, fuel exports, ore and mineral exports and manufactured exports (each as % of merchandise exports). Exports by trade partners are from the IMF’s direction of trade statistics (DoTS). Exports by trade partners were used to compute the weighted trade partner growth as described in Beny and Cook (2009). From the matrix of exports by trade partner a weighted matrix was obtained, which was multiplied by the GDP growth of each trade partner, giving a matrix of weighted partner growth for each country in each time period.
From the descriptive statistics shown in Table 1, it can be observed that during the entire period the yearly average GDP per capita growth of all the countries under study was 2.45 %, and a clear difference existed between the period 1990–1999 and the period related to the commodities boom (2000–2010) for both LAC and non-LAC countries. In the case of non-LAC countries, their growth rate increased from 2.19 to 2.72 % during the commodities boom; for LAC countries this increment was lower, from 2.07 to 2.56 %.
Table 1 Descriptive statistics: mean of the economic variables
Annual growth of capital formation for LAC countries was 8.13 % during 1990–199 but fell to 6.01 % during 2000–2010; capital formation was 4.91 % for non-LAC countries during 1990–1999 and rose to 5.59 % during 2000–2010. For non-LAC countries in the period 1990–1999 export trade partners’ average growth was 2.74 %, while for the LAC countries it was 2.09 %, but during the period 2000–2010 the trade partners’ growth increased more for LAC countries than non-LAC countries, reaching a slightly higher rate; LAC countries’ trade partners had an average growth of 8.88 % and non-LAC countries, 8.51 %. The annual growth of exports decreased on average in the boom period for all countries in study, but LAC countries experienced a decline of 2.61 % points while non-LAC countries experienced a decline of only 0.86 % points. The sums of the merchandise export shares shown in Table 1 do not sum to 100 % because of unclassified trade.