1. Introduction
Economies rich in natural resources tend to grow at a slower rate and have inferior development outcomes than those without natural resources. This puzzling phenomenon has been referred to as the “resource curse” hypothesis and was initially proposed by Auty [
1]. The resource curse was typically observed in many African countries that are rich in minerals but have remained at the least developed stage, whereas East Asian countries have achieved the highest growth performance worldwide without natural resources during the post-World War II period. The resource curse hypothesis has been analyzed empirically and theoretically in a number of studies, with the majority providing evidence to support this hypothesis (e.g., [
2,
3,
4,
5,
6,
7,
8,
9,
10]).
There have also been debates aiming to explain the factors and channels behind the existence of the resource curse. From a macroeconomic perspective, natural resource development and dependence are considered to crowd out manufacturing activities (referred to as Dutch disease, e.g., [
3,
4,
11,
12,
13]) and bring macroeconomic instability into an economy through the volatility of resource prices (e.g., [
14,
15]). From the aspects of political economy and governance, natural resource abundance accelerates rent-seeking behaviors, corruption, and internal wars (e.g., [
16,
17,
18,
19,
20,
21,
22]).
To solve the resource curse, theoretical approaches have traditionally been proposed, such as pricing, taxation, and the optimal extraction path of natural resources (e.g., [
23,
24,
25]). However, these approaches have been criticized for their normative nature and limited practicability [
26]. Alternatively, natural resource funds, as an explicit fiscal tool, have become one of the main targets for policy debates to address the resource curse. Their theoretical purpose is that these funds, by insulating the economy from the fluctuations of resource prices and political pressures, stabilize the macroeconomy and finance the investments and savings necessary for future generations (e.g., [
27,
28,
29,
30,
31]).
Empirical studies on the effectiveness of resource funds have produced mixed and inconclusive results. Evidence can be divided into the following three categories: arguments supporting the effectiveness of resource funds (e.g., [
30,
32]), arguments providing conditional support for the effectiveness of resource funds under high governance and robust fiscal rules (e.g., [
28,
33]), and arguments opposing their effectiveness (e.g., [
34,
35]).
To enrich the evidence on funds’ evaluation, this study aims to reexamine the effectiveness of 54 natural resource funds in 41 resource-rich countries according to funds’ objectives via an econometric method using panel data. The natural resource funds are classified into three types based on their objectives: stabilization, investment, and savings funds [
29,
36]. Accordingly, the research question is how effectively the funds have achieved their own objectives. The biggest contribution of this study is the demonstration of fund-specific evaluation: this study evaluates each fund’s effectiveness using each criterion corresponding to each objective. Literature has evaluated funds for specific countries or assessed all funds using a single criterion. Another contribution is to employ an econometric approach. To date, most studies have engaged in the qualitative, conceptual, and comparative assessment of resource funds in selected countries, while a limited number of studies have applied a quantitative approach to funds’ roles in fiscal and macroeconomic contexts.
The main conclusions of this study are highlighted as follows. The econometric estimations identify the effectiveness of stabilization funds in reducing the volatility of government expenditure and the primary balance, as well as the effectiveness of investment funds in increasing investment rates. They also confirm the facilitation of funds’ effectiveness under a combination of funds’ operations and high governance.
The remainder of this paper is organized as follows.
Section 2 reviews the literature related to the evaluation of resource funds and further clarifies the contributions of this study to the existing literature.
Section 3 presents an empirical analysis of fund evaluation. Further,
Section 4 presents and discusses the results, while
Section 5 concludes the paper.
2. Literature Review and Contributions
This section reviews the literature on the empirical evaluation of natural resource funds and clarifies the contributions of this study to the literature. As mentioned in
Section 1, empirical studies on the effectiveness of resource funds have produced mixed and inconclusive outcomes. The evidence can be classified into three categories: arguments supporting the effectiveness of resource funds, arguments providing conditional support for the effectiveness of resource funds under high governance and robust fiscal rules, and arguments opposing their effectiveness (see
Table 1 and
Table 2).
The first category, which represents arguments supporting resource funds, comprises both qualitative and quantitative studies. Regarding qualitative studies, specific stabilization and savings funds in selected countries are examined and cited as successful examples: Kuwait [
41]; Kuwait, Norway, Chile, and the state of Alaska in [
40]; Kazakhstan, Azerbaijan, and Norway [
39]; and the states of Alaska and Alberta [
32]. For quantitative studies, econometric approaches using panel data are applied to identify the effectiveness of funds using the criteria of monetary performance [
43], fiscal performance [
33,
38], governance [
30,
31], and financial resilience [
37]. A macroeconomic general equilibrium model also identifies the effectiveness of stabilization funds in the Russian Federation [
42]. Among the studies above, the representative one is Tsani [
30,
31] proving the association between resource funds, governance and institutional quality in resource-rich countries. They suggest that resource funds provide a useful insulation tool against the resource curse in the hands of the policy makers.
The second category represents the argument that resource funds have worked well under high governance and robust fiscal rules. In the qualitative analyses, the role of institutional capacity in funds’ success is emphasized in developing countries [
28,
45,
47], and fiscal discipline and rules have been found to be the prerequisites for funds’ workability [
40,
46,
49], while ensuring transparency is essential for fund management [
27,
44,
48]. In their quantitative study, Crain and Devlin [
51] conduct an econometric analysis using panel data and show that fund establishment reduces fiscal volatility in Chile and Norway, whereas it increases volatility in oil-exporting countries; they speculate that the difference comes from the fiscal policy framework. Allegret et al. [
50] construct a dynamic stochastic general equilibrium model and show that the combination of oil stabilization funds and policy rules contributes to preventing the Dutch disease effect. In this category, the representative study is Sugawara [
33] identifying the interaction effects between funds’ operations and political institutions and between funds’ operations and fiscal rules. It clearly shows that political institutions and fiscal rules in managing stabilization funds are significant factors in reducing the government expenditure volatility.
In the third category, which represents arguments opposing resource funds, Davis et al. [
34], using both econometric evidence and country case studies, argue that the establishment of a resource fund does not have an identifiable impact on government spending, while countries with more prudent expenditure policies tend to establish a fund, rather than the fund itself leading to an increased expenditure restraint. They also highlight the fund’s limited ability to coordinate with the budgetary process and the duplication of expenditures in the case of weak monitoring. These arguments are followed by case studies and qualitative analyses, such as those of Eifert et al. [
54], Devlin and Titman [
53], and Villafuerte et al. [
52]. Based on econometric analyses using panel data, Ossowski et al. [
35] show that the introduction of oil funds has had no impact on fiscal outcomes, while emphasizing the importance of sound institutions and public financial management systems. Ouoba [
36] demonstrates that resource funds have a negative and significant effect on economic growth.
The main contribution of this study is that, using an econometric approach, it adds to the existing quantitative evidence on the effectiveness of resource funds, the findings on which have been inconclusive in previous studies. Resource funds have been developed relatively recently, and this short timeframe has put practical limitations on econometric approaches. Therefore, enriching quantitative evidence is important for reaching robust conclusions.
The biggest contribution of this study is the demonstration of fund-specific evaluation. Resource funds are classified into three types based on their objectives: stabilization, investment, and savings funds, and the research question of this study is how effectively the funds have achieved their own objectives. This question is unique and different from the previous studies because the previous studies have evaluated individual funds for specific countries or assessed all funds using a single criterion such as fiscal performance, monetary performance, economic growth, or governance.
3. Material and Methods
This section conducts an econometric analysis of the evaluation of resource funds. It starts by describing the variables and data for the estimation and then clarifies the estimation methodology.
3.1. Variables and Data Collection
This subsection describes the variables and data collection for the subsequent econometric estimation. The estimation equation includes four dependent variables (the indicators for evaluating the effectiveness of funds according to their objectives), three explanatory dummies for the operations of the three types of funds (stabilization, investment, and savings), and other six explanatory variables for controlling time-varying country-specific effects. The variables used to estimate the effectiveness of the funds are listed, along with their measurement and data sources, in
Table 3, and their descriptive statistics are presented in
Table 4. A detailed description of each variable is provided after
Table 4.
The dependent variables specify four types of indicators to evaluate the effectiveness of funds according to their objectives. Data for all indicators are retrieved from the World Economic Outlook (WEO) Database of the International Monetary Fund (IMF). This study, based on IMF’s [
29] classification of sovereign wealth funds into four types—(1) stabilization funds, (2) pension reserve funds, (3) reserve investment funds, and (4) savings funds—classifies funds into three types by merging types (2) and (4) above based on their objectives, as in Ouoba [
36]. As previously mentioned, the types of funds considered here are stabilization, investment, and savings funds, with the list of analyzed funds comprising 54 funds in 41 resource-rich countries (see
Table 5). The first two indicators are used to evaluate stabilization funds. The first indicator,
g_exp, represents the volatility of government expenditure, expressed by the absolute value of the deviation from the period average of “general government total expenditure as a percentage of gross domestic product (GDP).” The second indicator,
g_pbl, denotes the volatility of government primary balance, expressed by the absolute value of the deviation from the period average of “general government primary net lending/borrowing as a percentage of GDP.” The third and fourth indicators,
inv and
sav, examine the investment and savings funds, and represent “total investment” and “gross national savings” as a percentage of GDP, respectively.
The three explanatory dummies denote the operations for the three types of funds:
f_sta for stabilization funds,
f_inv for investment funds, and
f_sav for savings funds. The effectiveness of funds can be identified when the coefficient on
f_sta is significantly negative and those on
f_inv and
f_sav are significantly positive. As in Sugawara [
33], this study assumes that it takes five years for a fund to operate substantially and have a tangible effect after its establishment. Therefore, when the fund is established in year
t, the dummy takes a value of 1 in year
t + 5, and 0 otherwise.
The other explanatory variables for controlling time-varying country-specific effects are represented by six indicators: economic growth, inflation, population, openness, resource dependence, and governance. These indicators are selected from those commonly used in more than three out of the six previous econometric studies listed in
Table 2 (the time-invariant country-specific variables such as political institutions in
Table 2 are dealt with by country fixed effects in this study). The first three indicators, taken from WEO, are “GDP in constant prices as percent change” (
gdp), “average consumer prices as percent change” (
inf), and “population by millions of persons as logarithm” (
pop); the population data are transformed into logarithms to avoid scaling problems in the estimation. The other two indicators, retrieved from the World Development Indicators (WDI) of the World Bank (
https://data.worldbank.org/, accessed on 1 July 2022), are “sum of exports and imports of goods and services as a percentage of GDP” (
top) and “total natural resource rents as a percentage of GDP” (
nrr). The last indicator represents the governance of a country’s managing funds, whose data are taken from the World Governance Indicators (WGI) of the World Bank (
http://info.worldbank.org/governance/WGI/, accessed on 1 July 2022). This indicator includes the following six indexes: voice and accountability (
voa), political stability and absence of violence/terrorism (
pos), government effectiveness (
gve), regulatory quality (
req), rule of law (
rol), and control of corruption (
cor). This study also computes the average of the six indexes above as a total index (
gov). The index ranges from −2.5 (weak governance) to 2.5 (strong governance), with the world average being approximately zero. All explanatory variables in this category are lagged by one year. As they might be endogenous to the model, there is a need to avoid the issue of reverse causality with the dependent variables.
3.2. Panel Data Setting
Based on the above setting of the variables, this study constructs panel data using annual data for 1996–2020 for 54 natural resource funds in 41 resource-rich economies (see
Table 4). The sample period starts from 1996 because this study considers the governance index of the country managing the funds, and the WGI database representing the governance index is available only after 1996.
For the subsequent estimation, the study investigates the stationary property of the constructed panel data by employing panel unit root tests: the Levin, Lin, and Chu test [
55] as a common unit root test and the Fisher–Augmented Dickey-Fuller (ADF), Fisher–Phillips–Perron [
56,
57], and Im, Pesaran, and Shin tests [
58] as individual unit root tests. The common unit root test assumes the existence of a common unit root process across cross-sections, whereas the individual unit root test allows individual unit root processes that differ across cross-sections. These tests are conducted based on the null hypothesis that a series of panel data in levels has a unit root by including the “intercept” and “trend and intercept” in the test equations.
Table 6 shows that the Levin, Lin, and Chu test rejects the null hypothesis of a unit root at the conventional significance level for all the variables in both test equations. The individual unit root tests do not necessarily reject the null hypothesis in all cases; however, the Fisher–ADF test rejects it at the conventional level for all variables in the test equation, including the intercept. Therefore, we assume there is no serious problem with the existence of unit roots in the panel data and use the panel data in levels for the estimation.
3.3. Model Specification and Estimation Method
The equation for the econometric estimation, following Sugawara [
33] and Ouoba [
36], is as follows:
Subscripts i and t denote the sample country and year, respectively. effect represents the indicators of funds’ evaluation and comprises volatility of government expenditure (g_exp), primary balance (g_pbl), investment rate (inv), and saving rate (sav). fund shows funds’ operation and comprises the funds for stabilization (f_sta), investment (f_inv), and saving (f_sav). Indicators g_exp and g_pbl correspond to the evaluation of f_sta, in which coefficient α1 is expected to have a negative sign because the stabilization fund is supposed to reduce the volatility of government expenditure and the primary balance. Indicators inv and sav correspond to f_sta and f_inv, respectively, and in this combination, coefficient α1 is expected to be positive because the investment and savings funds are supposed to increase investment and saving rates, respectively.
X denotes the control variables and includes indicators of economic growth (gdp), inflation (inf), population (pop), trade openness (top), resource dependence (nrr), and governance (gov). fi and ft show time-invariant country-specific fixed effects and country-invariant time-specific fixed effects, respectively; ε denotes the residual error term and α0…3 stand for the estimated coefficients.
The equation contains the interaction term of governance (
gov) and funds’ operation
fund as in Sugawara [
33]. This interaction term, reflecting the arguments of the previous studies in
Section 2, shows that resource funds work well under the conditions of high governance and robust fiscal rules and differentiates fund effectiveness with and without quality governance. Coefficient α
3, similar to α
1, is expected to be negative in the estimation of stabilization funds and positive in those of investment and savings funds.
This panel estimation is controlled by country-specific and time-specific fixed effects represented by
fi and
ft, respectively. From a statistical perspective, the Hausman specification test is generally utilized to choose between the fixed-effect and random-effect models [
59]. However, this study applies the fixed-effects model because it places a premium on the existence of exogenous country- and time-specific factors, where adopting the fixed-effects model contributes to alleviating the endogeneity problem by absorbing unobserved time-invariant heterogeneity among sample countries. As shown by the previous quantitative studies in
Table 2, factors such as political institutions are assumed to be correlated with funds’ effectiveness (not distributed randomly among sample countries). In the time series, external shocks, such as the global financial crisis of 2008–2009, might affect fund performance. As a specification ignoring these effects leads to inefficient estimation, they should be controlled for by incorporating country- and time-specific fixed effects into the specification.
Before the panel estimation, we investigate multicollinearity among the explanatory variables.
Table 7 reports the bivariate correlations and variance inflation factors (VIF), which is a method of measuring the level of collinearity between regressors. This reveals that the total governance index (
gov) and its six components (
voa,
pos,
gve,
req,
rol, and
cor) have a high bivariate correlation in each combination and high VIF values that are far beyond the criteria of collinearity, namely, 10 points. Therefore, the equation includes governance indicators as independent regressors.
Regarding the estimation technique, this study applies the ordinary least squares (OLS) and Poisson pseudo-maximum likelihood (PPML) estimators. The reason for applying the PPML estimator is that the sample data, including those of developing countries, would be plagued by heteroskedasticity and autocorrelation; in which cases, the OLS estimator leads to bias and inconsistency in estimates. The PPML estimator corrects for heteroscedastic error structure across panels and the presence of autocorrelation with panels, as Silva and Tenreyro [
60] and Kareem et al. [
61] suggest. Therefore, both estimators are applied to ensure the robustness of the estimations. We use EViews (version 12) as software to process the data and conduct all the estimations in this study.
4. Results and Discussion
Table 8 and
Table 9 report the estimation results for evaluating stabilization funds in terms of the volatility of government expenditure and primary balance, respectively, and
Table 10 and
Table 11 show those for evaluating investment and savings funds, respectively. All tables include the results of the OLS and PPML estimations with the total governance index and PPML estimations with each component of the governance index. The usage of the PPML estimator is justified, because the Durbin-Watson statistics in the OLS estimations do not meet the criterion to reject the existence of autocorrelation and the PPML estimator corrects the autocorrelation problem.
The main conclusions are as follows. Regarding the estimation of stabilization funds in
Table 8 (with the indicator of
g_exp) and
Table 9 (
g_pbl), the coefficients on the fund (
f_sta) are significantly negative for both the OLS and PPML estimations with the total governance index and in the majority of the PPML estimations with the components of the governance index. In the interaction term with the governance index (
f_sta*
gov), all coefficients are significantly negative, except in the case of
g_exp for the OLS estimation. As expected, these results suggest that stabilization funds effectively reduce the volatility of government expenditure and primary balance, and that higher governance facilitates fund effectiveness. Focusing on the PPML estimation with the total governance index, the operation of stabilization funds reduces the volatility of government expenditure by 13.6, and their operation under high governance reduces it by 33.2%.
In the estimation of investment funds in
Table 10 (
inv), the fund coefficients (
f_inv) are significantly positive in the PPML estimation (positive but insignificant in the OLS estimation) with the total governance index and in the majority of the PPML estimations with the components of the governance index. In the interaction term with the governance index (
f_inv*
gov), all coefficients are significantly positive in the PPML estimation with all governance indexes. These results imply that investment funds effectively raise the investment rate, and that higher governance facilitates their effectiveness. There seem to be multiple channels through which investment funds increase the investment rate: the government itself could increase public investment, while public investment in infrastructure, for instance, could induce private investment. Focusing on the PPML estimation with the total governance index, the operation of investment funds increases the investment rate by 9.8%, and their operation with high governance increases it by 46.8%.
In the estimation of savings funds in
Table 11 (
sav), the fund coefficients (
f_sav) are insignificant in all estimations, and those on the interaction term are negative in the majority of the estimations, which is against this study’s expectations. These results seem to come from the limitation of sample size: only Chile and Gabon’s funds are considered as estimation targets in the sample period from 1996 to 2020.
The estimation results for the control variables are as follows. Economic growth (gdp) has negative effects on fiscal volatility and positive effects on investment and saving rates. It is speculated that economic growth leads to a lower fiscal stimulus and an increase in investments and savings. Inflation (inf) has ambiguous effects on fiscal volatility and negative effects on investment and saving rates, probably because it increases economic uncertainty. Population size (pop) has a negative impact on fiscal volatility due to insensitivity to shocks in large economies, but ambiguous impacts on investment and saving rates. Trade openness (top) shows mixed results. Meanwhile, resource dependence (nrr) has positive effects on fiscal volatility and investment rates, which might reflect the possible existence of the resource curse in resource-rich economies. Governance (gov, voa, pos, gve, req, rol, and cor) has negative effects on fiscal volatility and investment rates, and positive effects on saving rates.
Table 12 summarizes the results for fund effectiveness.
In summary, the estimation identifies the effectiveness of stabilization funds in reducing the volatility of government expenditure and primary balance and the effectiveness of investment funds in increasing investment rates. It also confirms the facilitation of fund effectiveness by the combination of fund operations and high governance. These outcomes are consistent with those of previous studies from the first and second categories (the arguments supporting the effectiveness of resource funds and those providing conditional support for the effectiveness of resource funds under high governance and robust fiscal rules) in
Section 2, in particular with Bagattini [
38], Sugawara [
33] and Crain and Devlin [
51] on the effectiveness of stabilization funds in terms of fiscal performances. However, the main contribution of this study is demonstrating fund-specific evaluation and identifying the effectiveness of funds according to their objectives, particularly the effectiveness of investment funds in increasing investment rates.
The practical implications of the obtained results can be discussed as follows. Regarding stabilization funds combined with robust fiscal rules, the reduction of fiscal volatility leads to the stabilization of resource-rich economies. The resource curse for resource-rich economies contains their macroeconomic instabilities caused by abrupt fluctuations of commodity prices in the world market. Further, their governments lacking institutional qualities fall into the “voracity effect”, which means that a positive shock in government revenues (e.g., windfall gains from natural resources) results in a more-than-proportional increase in discretionary spending (Tornell and lane [
62]). The voracity effect accelerates pro-cyclically boom-and-bust cycles of the economies. However, the fiscal smoothing under the operation of stabilization funds provides a counter-cyclical buffer to mitigate commodity price shocks, thereby contributing to the stabilization of resource-rich economies.
As for investment funds with high governance, the increase in investment rates mitigates the Dutch disease effect, thereby contributing to sustainable growth for resource-rich economies. Dutch disease, one of the resource curse phenomena, demonstrates that natural resource development crowds out manufacturing activities (Corden and Neary [
11]). As a counterargument to the Dutch disease hypothesis, Sachs [
12] argues that Dutch disease could be reversed if natural resource earnings were used not for consumption but for public investment, because the positive benefits of increased public investment on the non-energy traded sector through productivity improvement would outweigh any negative consequences of Dutch disease. Thus, the increase in investment rates under the operation of investment funds, meaning capital accumulation through public investment and induces private investment, alleviates the Dutch disease effect, thereby sustaining economic growth of resource-rich economies.
5. Conclusions
This study aims to examine the effectiveness of natural resource funds in resource-rich countries according to funds’ objectives, using an econometric method and panel data. The main contribution of this study is that it demonstrates fund-specific evaluation.
The study classifies funds into three types based on their objectives: stabilization, investment, and savings funds, and then evaluates the effectiveness of each fund type using each criterion corresponding to each objective. The econometric estimations identify the effectiveness of stabilization funds in reducing the volatility of government expenditure and primary balance, as well as the effectiveness of investment funds in raising investment rates. They also confirm the facilitation of fund effectiveness under the combination of a fund’s operations and high governance. For instance, the operation of stabilization funds reduces the volatility of government expenditure by 13.6%, and their operation with high governance reduces it by 33.2%; further, that of investment funds pushes up the investment rate by 9.8%, and their operation with high governance increases it by 46.8%.
The practical implications of the obtained results are that the fiscal smoothing under the operation of stabilization funds provides a counter-cyclical buffer to mitigate commodity price shocks, thereby contributing to the stabilization of resource-rich economies, and that the increase in investment rates under the operation of investment funds alleviates the Dutch disease effect, thereby sustaining economic growth of resource-rich economies.
A limitation of this study is that, although the effectiveness of investment funds is verified by an econometric estimation, its effectiveness should be supported by case studies in selected countries. Additionally, the effectiveness of savings funds is not confirmed in this study due to the lack of sample data. Future research should thus demonstrate the significance of investment and savings funds.