This paper examines how public spending, particularly on agricultural research and development, affects rural poverty. This work focuses on the provision of public goods because the primary responsibility of governments is to provide public goods that represent goods and services that are under-provided due to missing markets or market imperfections. Investment in public goods provides factors of production that are almost by definition rarely provided by the private sector. For this reason, such investment can reasonably be expected to fill a gap that is not filled by the private sector.
Spending on public goods generally produces benefits that tend to be more beneficial to the poor than the provision of private goods that are usually monopolized by lobbies. For example, an adequate stock of rural public goods, including agricultural research and development, can help to sustain farm incomes. Moreover, the rural sector in many developing countries is large enough in the unskilled labour market to significantly affect the real wages of unskilled workers, even at the national level (López (2004). Thus, a dynamic rural productive sector is a vital source of employment for unskilled workers because it can play a role in supporting higher real wages. Since most of the poor are unskilled workers, these effects can be important for poverty reduction.
2.1- Model
The theoretical model used in this research is based on that of López (2004). The author used this model to analyse the effects of rural public spending on agricultural growth and rural poverty in Latin America. The approach consists of specifying a reduced-form model that explains per capita agricultural value added by exogenous variables. It considers the following production function:
$$Q=F(L,K,X,A){\text{ }}\left( 1 \right)$$
Where Q is agricultural output, K is a vector of farmer-owned inputs, L is labour used in the sector, X is a vector of purchased inputs, and A is a productivity index.
Agricultural value added is defined as the output of primary factors, K, L. Thus,$$G(p,v,L,K,A) \equiv \mathop {\hbox{max} \left{ {pF(L,K,X,A) - vX} \right}}\limits_{{}} {\text{ }}\left( 2 \right)$$
where G( ) is agriculture GDP, p is output price and v is a vector of purchased input prices. The function G( ) is a (dual) revenue function and must satisfy certain conditions: The most important from our point of view is that, apart from being increasing and concave in L and K, is also homogenous of degree one in K and L. This implies that we can express per capita agriculture GDP as:$$\mathop g\limits^{{}} \left( {p,v,k,A} \right) \equiv \frac{{G\left( {p,v;K;L,A} \right)}}{L}{\text{ }}\left( 3 \right)$$
Thus, per capita GDP is a function of output and purchased input prices, and the per capita values of the farmers owned assets, k, as well as of the productivity factor, A. It is increasing in p, k and A, and decreasing in v. The remainder of this section is devoted to the estimation strategy of the per capita agricultural GDP function,
(g(p,v,k,A)). As a result, it is assumed that the prices of output and purchased inputs are determined by world prices, national policies including trade policy, as well as the performance of the non-farm sector that may affect marketed products. Thus,$$p=\phi \left( {p*,H,Y} \right);{\text{ v=}}\psi \left( {v*,H,Y} \right){\text{ }}\left( 4 \right)$$
where a star indicates world prices, H stands for a vector of government policies affecting domestic prices and Y reflects conditions in sectors other than agriculture, but that could affect prices relevant to agriculture. The variables, p*, H, and Y are all subject to change over time as world market conditions, policies, and non-agricultural growth conditions vary.
The variables k and A are also endogenous and affected by the exogenous variable, world market conditions, government policies and the performance of the non-agricultural economy.$$k=k(p,v,A,H,Y);{\text{ A=A}}\left( H \right){\text{ }}\left( 5 \right)$$
It is assumed that the level of agricultural assets per capita k increases with rising agricultural prices, falling input prices and rising levels of agricultural productivity. Similarly, it is assumed that A increases with the level of public spending, particularly on public goods such as research and development and education. Government policies also affect the accumulation of agricultural assets per capita through both commodity and input prices, technical assistance, etc., and the level of agricultural productivity. Similarly, conditions in the non-farm sector affect agricultural value added through market effects associated with demand conditions for agricultural commodities, as well as through non-trade mechanisms. Combining (4) and (5) we obtain a reduced form function of k,$$k=\mathop \Omega \limits^{{}} \left( {p*,v*,H,Y} \right){\text{ }}\left( 6 \right)$$
The H vector can be decomposed into several dimensions of government policies such as trade policies and public spending. In this work, the focus will be on public spending on agricultural research and development. Thus, we can decompose the H vector into R (public expenditure on agricultural research and development) and E (training policy) and T (trade policy).
Thus, k can be written as follows:$$k=\Omega \left( {p*,v*,T,R,E,Y} \right){\text{ }}\left( 7 \right)$$
It is expected that k does not decrease in p*, Y, R, E, T and does not increase in v*. Substituting (4), (5) and (7) in (3) yields a specification of the reduced form of the per capita agricultural value added function$$g=g(\mathop {p*}\limits_{+} ,\mathop {v*}\limits_{ - } ,\mathop {T,}\limits_{+} \mathop R\limits_{+} ,\mathop E\limits_{+} \mathop {,Y}\limits_{+} ){\text{ }}\left( 8 \right)$$
The signs under the variables indicate the expected effects of these different exogenous variables on per capita agricultural value added. Eq. (8) forms the basis for the specification of the estimation model.
Within the framework of this study, poverty is analysed through the monetary approach. This option is justified by the fact that it is monetary poverty that attracts the most attention from policy makers. Moreover, being linked to the level of household income, monetary poverty can be considered not only as a result of production conditions, but also as a consequence of the institutional arrangements that are put in place to stimulate the process of wealth creation (Savadogo et al,
2012). As a result, rural poverty is approximated to agricultural income. This choice is based on the fact that an increase in income is accompanied by a decrease in poverty. This option is supported by Kanbur and Squire (
2000) who show that improving rural incomes is an important strategy for reducing rural poverty. Similarly, by agreeing with Boussard et al (
2006), it is proven that poverty is linked to purchasing power and therefore income. The poor are those who cannot afford the goods needed to access a satisfactory level of available kilocalories. Moreover, it is worth emphasizing the dynamic nature of income, which can generate a vicious circle of poverty over time without external intervention. Those who are poor year-round are more likely to be poor year-round. Therefore, poverty is analysed using a dynamic approach. It is therefore possible to adopt a dynamic model in which the lagged dependent variable is included as an additional explanatory variable to capture the potentially slow adjustment of agricultural value added to policies and other conditions. In the light of these arguments, the following sub-section defines the variables retained in the model. From (8) it is possible to deduce the agricultural income equation that will capture rural poverty.
2.2- Data description
The analysis is based on panel data covering the period 2000–2016. The study covers seven (07) countries out of the eight (08) WAEMU countries. Guinea Bissau was excluded from the analysis due to unavailability of data. The choice of the study period is linked to the availability of data on the variables. The data mainly come from the World Bank's World Development Indicators (WDI, 2017) database, the World Food and Agriculture Organization (FAO), and the African Development Bank (AfDB).
2.3- Definition of model variables
2.3.1- Dependent variable
Rural poverty indicator
In this paper, the dependent variable is an indicator of agricultural income that is approximated to rural poverty. It is represented by the logarithm of the ratio of agricultural value added per capita to the international poverty line. Similar studies have used this indicator in their analyses. One can cite that of Savadogo et al (2012) which used this poverty indicator to analyse the standard of living of households in rural Burkina Faso in the context of decentralisation. Similarly, Sanfo (2010) analysed the effects of public agricultural policies on the fight against rural poverty in Burkina Faso using farm household income.
2.3.2- Explained variables
Public expenditure on agricultural research and development
Data on agricultural research and development expenditures (rdinvest) are provided by IFPRI and include expenditures related to the administrative operations of government agencies engaged in applied research and experimental development in agriculture. These expenditures include grants, loans and subsidies to support applied research and experimental development in agriculture carried out by research institutes and universities.
The number of agricultural researchers per one hundred thousand (100,000) producers (nagriresearch)
The number of agricultural researchers per one hundred thousand (100,000) producers (nagriresearch) was also included. This indicator, provided by FAO, includes all those with official researcher status employed by public agencies, non-profit organizations and higher education institutions to carry out studies in the agricultural field.
Education
The effects of education on rural poverty were also considered in the light of the theoretical and empirical literature. According to human capital theory, education improves the productivity of economic agents. Thus, a high level of education should be accompanied by a high level of income. Lau et al (1991) showed that education had an effect on agricultural productivity when the farmer had an educational level of more than three years. The authors carried out this study using data from more than fifty countries, including some West African countries. Moock (1981) and Rauf (1991) found similar results in the eastern region of Kenya. Thus, Primary completion rate (eduprim) was used to take into account the effects of education on agricultural income. A positive sign of this variable is expected. Table 1 provides a summary of the variables used and their sources. The expected signs are also presented.
Value added of non-agricultural products
This is the manufacturing sector, which includes tabulation category D in divisions 15 to 37 of the International Standard Industrial Classification (ISIC) of all economic activities. It is the physical or chemical transformation of component materials into new products, whether the work is done by machine or by hand, whether it is done in a factory or in the worker's home, and whether the products are sold wholesale or retail. This includes the assembly of components of manufactured products and the recycling of waste.
Value added is the net output of a sector after adding up all outputs and subtracting intermediate inputs. It is measured in current US dollars. This indicator is provided by the AfDB. A positive sign of this variable is expected.
Trade Opening rate (openr) :
It is given by the sum of exports and imports in relation to GDP. A positive sign is expected. According to the theory of comparative advantage (Ricardo, 1817), the absence of restrictions on trade can favour gains from trade.
Table 1
Summary presentation of model variables
Variables of model | Definition of variables | Source | Expected sign |
rinc | Agricultural value added per capita relative to the poverty line of country i at the date t | Calculated by the author from FAOSTAT data | Dependent value |
rincit−1 | Delayed one-year value of the log of agricultural value added per capita relative to the poverty line of country i at the date t | Calculated by the author from FAOSTAT data | + |
rdinvest | Public spending on agricultural research and development | IFPRI database | + |
nagriresearch | Number of agricultural researchers per hundred thousand producers | FAOSTAT | + |
primeduc | Primary completion rate | AfDB database | + |
openr | Trade opening rate | Calculated by author from World Bank (WDI) data | + |
nava | Value added of the non-agricultural sector | Calculated by author from World Bank (WDI) data | + |
2.4- Empirical model specification
The inclusion of income dynamics in the model leads to the following specification:
\(lrin{c_{it}}=\alpha lrin{c_{i,t - 1}}+{\beta _1}lprimed{u_{i,t}}+{\beta _2}lrdinves{t_{i,t}}+{\beta _3}nagriresearch+{\beta _4}open{r_{i,t}}+{\beta _5}lnav{a_{i,t}}+{\mu _i}+{\varepsilon _{i,t}}{\text{ }}\left( 9 \right){\text{ }}\) i represents the country and t the time
\(lrinc\) is the log of agricultural value added per capita normalized to the international poverty line
\(leduprim\) represents public spending on education measured by total enrollment of primary students
\(lrdinvest\) represents public spending on agricultural research and development
\(nagriresearch\) number of agricultural researchers per 100,000 producers
\(openr\) is an indicator of trade openness
\(\ln ava\) is the value of non-agricultural GDP per capita
\(\mu\) represents the individual effects
\(\varepsilon\) is the error term
2.5- Descriptive analysis
Table 2 presents descriptive statistics.
Table 2
Variable | Observations | Mean | Standard deviation | Min | Max |
Variable dépendante |
rinc | N = 119 | 1.214984 | .7969399 | .2365263 | 3.731752 |
Explanatory variables |
nagriresearch | N = 119 | 5.982426 | 2.436083 | 2.305695 | 9.868282 |
rdinvest | N = 119 | 29.11268 | 22.53258 | 5.498965 | 91.56726 |
openr | N = 104 | 62.63954 | 19.07883 | 27.86642 | 127.262 |
primedu | N = 99 | 51.04605 | 15.58608 | 18.87801 | 85.10817 |
nava | N = 119 | 1.08e + 09 | 1.17e + 09 | 1.08e + 08 | 5.74e + 09 |
Table 2 shows that the rural poverty indicator represented by agricultural value added per agricultural asset normalized to the poverty line is on average US$1.21. The maximum value observed is 3.73 US$ recorded by Côte d'Ivoire in 2014 against a minimum value of 0.23 US$ for Burkina Faso in 2000.
In terms of expenditure on agricultural research and development, the average for WAEMU countries is US$ 29,112,680, with a maximum of US$ 91,567,260 reached by Côte d'Ivoire in 2000, compared to a minimum of US$ 5,498,965 recorded by Niger in 2000. Concerning the number of agricultural researchers per 100,000 producers, UEMOA has an average of 6 researchers. Niger has more agricultural researchers (10) in 2011, whereas in 2008 it was the least endowed country with 3 agricultural researchers. In addition, it should be noted that the average primary completion rate is 51.05% with a maximum of 85.11% in Togo in 2014 against a minimum of 18.87% for Niger in 2000.
For the control variables, the average value added of non-agricultural products amounts to 1.08 billion US$ with a maximum of 5.74 billion US$ recorded by Côte d'Ivoire in 2014 against a minimum of 0.108 billion US$ recorded by Niger in 2000. With regard to trade openness, the average observed over the period amounts to 62.64%. The maximum value of trade openness is 127.26% and was observed in 2013 in Togo against a minimum value of 27.87% presented by Burkina Faso in 2013.
2.6- Estimation method
In Eq. (9), the lagged endogenous variable appears as the explanatory variable, so we are in a dynamic panel situation. In this case, standard econometric techniques such as OLS do not provide unbiased estimates of such a model. Indeed, the presence of the lagged explanatory variable makes the OLS and GCM estimators inefficient and non-convergent. Furthermore, when the number of periods is small or when the lagged dependent variable is correlated with individual effects, OLS estimation of this model leads to biased and non-convergent estimators. For Mickell (1981), in the case of inverse causality or omission of relevant variables, the OLS estimator is inconsistent and biased.
In the literature, GMM techniques are increasingly used to estimate dynamic panel models (Andrianaivo and Kpodar, 2011; Konté et al., 2017; Zmami, 2017; Amat, 2019). This method is adequate to deal with the problem of endogeneity of one or more explanatory variables, in particular the presence of the lagged dependent variable that gives a dynamic character to the panel specification. GMM estimation also provides solutions to the problems of simultaneity bias, inverse causality between different economic variables, and omitted variables. Indeed, not taking into account the problem of endogeneity in economic relations means making the strong assumption that, for example, the explanatory variables of the model are independent of the unobserved characteristics that distinguish the different countries.
There are, however, two estimators associated with GMMs. The first difference estimator (Arellano and Bond, 1991) and the system estimator (Blundell and Bond, 1998), which is an improved version of the first. One of the weaknesses of the first-difference estimator is that it is better suited for samples with sufficiently large N (individual dimension) and relatively small T (time dimension). It therefore has asymptotic precision weaknesses and instrument weaknesses that lead to biases in the finite samples.
The system estimator of Blundell and Bond (1998) simultaneously uses first difference and level equations to generate consistent estimators, even for finite samples, to overcome this problem. Differentiation eliminates the country-specific effect and thus the effect of omitted variables that are invariant over time. The first differences of the potentially endogenous explanatory variables are instrumented by their level lagged value, in order to reduce the simultaneity bias as well as the inverse causality bias, and under the assumption of no autocorrelation of errors in the level equation.
The endogenous explanatory variables of the level model are instrumented by their most recent first difference (the use of other delayed first differences would lead to a redundancy of moment conditions), under the additional assumption of "quasi-stationarity" of these variables. Thus, the Generalized Method of Moments (GMM) in system developed by Blundell and Bond (1998) is used to estimate the model, the results of which are presented in the following section.