Applying the Harrod-Domar model to the Sudanese economy in the period(1992-2018)

Prepared by the researche :  Dr. MOHAMED MASOUD MOHAMED IDRIS – SUDAN

Democratic Arabic Center

Journal of African Studies and the Nile Basin : Twenty-sixth Issue – June 2024

A Periodical International Journal published by the “Democratic Arab Center” Germany – Berlin

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Abstract

The study dealt with the application of the Harrod-Domar model to the Sudanese economy in the period (1992 – 2018). The study aimed to apply the Harrod-Domar model to the Sudanese economy by analyzing the factors affecting the internal resources gap, the external trade gap, and the effect of the internal gap on the external gap. The study used the historical approach and the descriptive analytical approach using standard methods. The study concluded that the variables of unused energy, production of raw materials, and capital productivity led to reducing the gap (savings – investment). The study proved that the variables of the real exchange rate, investment, and terms of trade led to reducing the gap (exports and imports). The study concluded that There is a significant impact of the internal resources gap on the external resources gap. To avoid wasting foreign exchange, ways must be found to raise the savings rate or capital productivity. After knowing the size of the larger gap, this gap must be filled in through foreign borrowing. The import and export gap will decrease provided that it increases. Exports at a faster rate than national income.

The first axis

Methodological framework and previous studies

First: The methodological framework

introduction :

The Harrod-Domar model is considered one of the most consistent and common models. It was developed in the 1940s and is associated with the names of the British economist Roy Harrod and the American Avery Domar. The model focuses on investment as a vital necessity for any economy, and shows the importance of saving in increasing investment as a requirement for capital. And its relationship to growth, the model assumes the existence of a relationship linking the quantitative size of the capital stock to the gross national product. This relationship and the problem of the ratio of capital to output is known in the economic literature by the capital factor. The Harold Domar model shows that achieving the development process requires increased saving, and thus rapid investment to increase the speed of Growth, and the basis of growth is that the capital that is created through investment in factories and equipment is the main determinant of growth, and it depends on the savings of individuals and companies who make possible investments. As for the ratio of capital to output – that is, the capital coefficient – it is simply a measure of investment productivity or capital.

There are external and internal factors that led to the failure of successive governments in Sudan to exploit the abundant natural and human potential and then implement development plans. The external factors were natural factors such as torrents, floods, drought, and desertification, in addition to tribal conflicts and civil wars, and of course, the outcome was migration from the countryside to the cities, where migrant farmers turned to marginal work, which led to a decrease in production and pressure on services. As for the internal factors, the most prominent of them is political instability, which led to poor executive management, a sagging job structure, and an accompanying increase in public spending. Diverting the purposes of external financing for development projects to consumer spending also led to a slowdown in growth, a decrease in incomes, and an increase in the severity of poverty, which means an inability to attract the required savings. The inefficiency of the executive apparatus was represented in poor planning and selection of development projects that can be divided into five categories: Development projects that did not see the light were transferred. Their budgets financed with foreign exchange for other purposes were marred by a lot of financial corruption, development projects that were incomplete and exceeded their completion date, projects that were completed but did not enter production, development projects that were completed and were operating at a low production capacity, and finally successful projects that were few in number. With the exception of oil extraction projects, roads and bridges, development projects have not yielded results as desired. Accordingly, the external debts that were brought in to implement these projects burdened the Sudanese economy with the debt being serviced externally. Unfavorable policies and distortions also caused the deterioration of productive sectors, with resources simultaneously directed to the services sector, especially the commercial and marginal ones.

the study Problem :

The problem of the study is to answer the following questions:

1. Is there a significant difference between the two gaps?
2. Did the economic policies of successive governments affect the performance of the two gaps?
3. How is the balance between the two gaps achieved?

Objective  of the study :

The study aimed to apply the Harrod-Domar model to the Sudanese economy by analyzing the factors affecting the internal resources gap, the external trade gap, and the effect of the internal gap on the external gap.

the importance of studying :

The importance of the study is to confirm the role of the Harrod-Domar model in achieving continuous economic growth, determining the rate of economic growth through the level of investment and its efficiency, and clarifying the role of technological progress in increasing the efficiency of investment, which leads to higher levels of economic growth.

Study hypotheses: The study relied on the following hypotheses:

1. The study assumes that there is no significant difference between the two gaps.
2. The economic policies of successive governments did not lead to achieving a balance between the two gaps.

Study methodology:

The study is based on the descriptive and analytical approach using standard methods and statistical tests. EViews software will also be used to analyze the study data.

Data sources:

Books, previous studies, reports and publications issued by the Bank of Sudan, the Ministry of Finance, the Central Bureau of Statistics, and the Internet.

The limits of the study :

Time limits: The research will cover the period 1992-2018.

place limits : Republic of Sudan.

Second: Previous studies

Gamal Mohamed study (2018)[1] : The research aims to assess the current situation of the most important economic variables affecting development rates. Consequently, it seeks to predict the most important economic variables affecting growth as well as the size of the gap in local resources in order to reach the targeted growth rate necessary to advance development. The research depends on quantitative and descriptive approaches which include estimating time-series equations for the variables during the period (1990- 2016), forecasting the economic variables studied until 2030, and applying the Harrod-Domar model. The results showed that capital, savings, investment, exports and national imports have taken a generally significant positive trend with an annual growth rate of about 11%, 9.6%, 12%, 11% and 11.5%, respectively. However, the marginal coefficient of capital / output was almost constant at 5.5 during the study period. The population growth rate was estimated to be 1.9%, while the GDP growth rate has fluctuated between 1.07% & 7.15% in 1991 and 2008 respectively with an average of about 4.28% during the same period. The results showed that the GDP growth rate has been significantly affected during period 2011 2014 due to the economic and political conditions experienced by the country. Forecasting results indicated that GDP, national capital, savings, investment and the value of exports and imports are expected to increase; however, the marginal coefficient of capital/ output to be constant during the forecast period. Results also showed that the development and investment rates dropped to 4% and 16% respectively .Therefore, the recourses gap increased from 161 billion pounds in 2017 to 256 billion pounds in 2030, besides the foreign trade gap increased from 143 billion pounds in 2017 to 229 billion pounds in 2030.

Study by Abdel Azeem Saleh(2006) [2]  :The study dealt with measuring and estimating the size of the development effort required to get rid of the development gap in the countries of the Organization of the Islamic Conference and its interpretation. It began by presenting the concept of the development gap and the development effort required to get rid of the development gap. Then it touched on the effects of economic backwardness, whether represented by low productivity, a high level of unemployment, or dependence on economic backwardness. Primary products as the basis of economic activity. The study then turned to measures of the development effort required to get rid of the development gap through income per person using official exchange rates and then using purchasing power parity. The study then turned to measures of the development effort required to get rid of the development gap through the human development index and the poverty index and concluded To the quantitative size of the development effort required from every Islamic country in order to get rid of the development gap. It also reviewed the interpretation of the development gap under classical theory, Adam Smith for the development gap through specialization, division of labor, and increasing yields, Malthus for the development gap through high population growth rates, then the Harrod-Domar model as an explanation of growth through capitalist accumulation and neoclassical growth theory, which presents the basic assumptions and tests hypotheses in explaining convergence or The divergence between developing countries, especially Islamic countries, and developed countries in levels of productivity and per capita income.

Study by Geerdink(2005)[3] : The study examined the impact of the economy’s transition from self-sufficiency to an open capital market, using the Harrod-Domar model to gain insight into whether open capital markets improve public welfare: First, using conflict theory, attention was paid to the microeconomic foundations of the model. The two-country model and the Leontief production function were used in an intergenerational environment, restricted by the transfer of more capital to the poor region in the short term, but what happens to the rich regions is unknown. Depending on the level and degree of transfer of capital from one region to another, the economic performance of the poor regions will increase in the short term. The worst that can happen is that the rich regions will be exposed to a decline in their economies. These results seem more appropriate to reality than to the view of neo-traditionalists.

The second axis

Theoretical framework

First: Harrod-Domar model

The Harrod-Domar model is a Keynesian model of economic growth that focuses on the relationship between production growth and capital accumulation. In contrast to neoclassical growth theory, the Harrod-Domar model emphasizes the importance of investment in creating economic growth. This model is based on the assumption that savings and investment are The main determinants of economic growth. The model is named after economists Roy Harrod and Evsee Domar who developed the model in the early 1940[4].

Investment: In the Harrod-Domar model, investment is the main driver of economic growth. As investment increases, output grows. This is because investment creates more capital, which in turn allows for more production. For example, if a country invests in new factories, it can produce more goods and services, leading to economic growth.

Savings: Savings play an important role in the Harrod-Domar model because they provide funds for investment. The more a country saves, the more it invests, and the more it grows. For example, if a country has high savings rates, it can invest in new infrastructure and technology, leading to economic growth.

Capital-Output Ratio: Capital-output ratio is the amount of capital required to produce a unit of output. In the Harrod-Dohm model, this ratio is assumed to be constant. This means that as output grows, the amount of capital needed to produce it increases. For example, if a country wants to double its output, it will need to double its capital stock.

Economic Growth: In the Harrod-Dohm model, economic growth is determined by the rate of investment. If a country invests at a high rate, it can achieve high levels of economic growth. However, if investment is low, growth will be slow or stagnant.

Technological progress: The Harrod-Domar model also recognizes the importance of technological progress in promoting economic growth. Technological improvements can increase productivity and efficiency, allowing the economy to produce more goods and services with the same amount of inputs[5].

Balanced Growth: The Harrod-Domar model emphasizes the importance of balanced growth, which means that all sectors of the economy should grow at the same rate. This is necessary to maintain stability and avoid imbalances that can lead to economic crises.

Overall, the Harrod-Domar model provides a useful alternative to neoclassical growth theory, highlighting the importance of investment, saving, and technology in promoting economic development.

Assumptions of the Harrod-Domar model:

(1) The basic assumption is that foreign and local sources are not interchangeable. However, if there is a foreign exchange deficit, it results from using domestic resources in the short term to earn foreign exchange, or saving foreign exchange by increasing import productivity.

(2) The Arab countries are considered a living example of the savings gap – the largest. Despite the availability of foreign exchange, these countries resort to purchasing and importing capital goods and labor force, and most of them have a skill problem that prevents maximum benefit from the availability of cash.

The role of savings and investment in the Harrod-Domar model:

The Harrod-Domar model offers an alternative approach to neoclassical growth theory by emphasizing the role of savings and investment in economic development. In this model, the rate of economic growth is determined by the level of investment relative to existing capital stock, and the ability of the economy to absorb new investments. Without generating inflation. Savings are an important factor in the model because they enable investment, which, in turn, drives economic growth. Based on the above, the role of savings and investment in the Harrod-Domar model is to take into account the following[6]:

1. The relationship between savings and investment: In the Harrod-Domar model, investment is the main engine of economic growth, and is financed through savings. The more savings an economy has, the more investment it can make, and the faster it can grow. This means that countries with higher savings rates are more likely to experience faster economic growth in the long run. For example, China has been able to achieve high rates of economic growth in recent years due to its high savings rate, which has enabled it to invest heavily in infrastructure and manufacturing.
2. The relationship between investment and productivity: In the Harrod-Domar model, investment is not only important for increasing capital stock, but also for improving productivity. Productivity improvements can come from a variety of sources, such as technological developments or improvements in management practices, But investment is often a key factor in these improvements. For example, a company that invests in new equipment or technology may be able to produce goods at a lower cost, which can improve its profitability and competitiveness.
3. The role of the government in promoting savings and investment: In the Harrod-Domar model, the government can play an important role in promoting economic growth by providing incentives for savings and investment. For example, tax incentives to save or invest can encourage individuals and businesses to save and invest more, which can lead to higher rates of economic growth in the long run.

The Harrod-Domar model emphasizes the importance of savings and investment in promoting economic growth. By understanding the relationship between saving, investment, and productivity, policymakers can design policies that encourage long-term economic growth.

The importance of technological progress in the Harrod-Domar model:

When it comes to economic growth, technological progress plays an important role. The Harrod-Domar model, an alternative to neoclassical growth theory, emphasizes the importance of technological progress in achieving sustained economic growth. In this model, the rate of economic growth is determined by the level of investment and the efficiency of this investment. Technological progress, in turn, increases the efficiency Investment, leading to higher levels of economic growth[7].

Here are some key points about the importance of technological progress in the Harrod-Dohm model:[8]

1. Technological progress enables economies to produce more output with the same amount of inputs. For example, advances in technology in the agricultural sector have allowed farmers to produce more crops with the same amount of land, labor, and capital. This increased efficiency leads to higher levels of economic growth.
2. Technological progress encourages innovation, which can lead to the development of entirely new industries and products.
3. Technological advances can also lead to improvements in infrastructure, such as transportation and communications networks. This improved infrastructure makes it easier for businesses to operate and expand, leading to economic growth.
4. Technological progress can improve the quality of life of individuals. For example, advances in healthcare technology have allowed the development of new treatments and cures, leading to longer and healthier lives.
5. This improved quality of life can indirectly contribute to economic growth by increasing the productivity of the workforce.

In general, technological progress plays an important role in the Harrod-Dohm model and in achieving sustained economic growth.

The importance of foreign aid in the Harrod-Domar model[9]:

Foreign aid is a critical component of the Harrod-Domar model. The model emphasizes that countries need capital formation to achieve long-term economic growth. However, many developing countries lack the resources to finance such investments. Foreign aid can help fill this gap by providing resources that can be used to finance investment projects. Injecting foreign capital can stimulate economic growth, which increases the country’s ability to repay its debts and attract more foreign investment. Therefore, the importance of foreign aid in the Harrod-Domar model is as follows:

1. Foreign aid can help capital formations in developing countries because they need to invest a large amount of capital to achieve long-term economic growth. However, many developing countries lack the resources to finance long-term investments[10].
2. Foreign aid can help fill this gap by providing resources that can be used to finance investment projects. For example, foreign aid can finance infrastructure development projects, such as building roads and bridges, which can improve market access and stimulate economic growth.
3. Foreign aid can help stimulate economic growth in developing countries, as this growth helps increase the country’s ability to repay its debts and attract more foreign investment. For example, foreign aid can be used to finance education and health care programs, which can improve the quality of capital. The country’s human capital can, in turn, lead to higher levels of productivity and economic growth.
4. Foreign aid can help reduce poverty, which is a major problem in many developing countries, such as providing food and shelter to the poorest members of society and improving their living standards.
5. Foreign aid can help promote political stability as economic growth and political stability are strongly linked.

Second: Economic growth

The concept and definition of economic growth:

       Economic growth can be defined as: “The increase recorded over a period of time, usually a year or successive periods of time, of an expansionary economic variable is the real net output[11].” It can also be defined as: “Economic growth is an automatic process of economic expansion, measured by quantitative changes occurring”[12].

         Through the previous definitions, we can define economic growth as: “It is the annual increase recorded as a percentage in the real domestic product.”

Measuring economic growth:

There are two indicators to measure economic growth:

Gross Domestic Product (GDP): It is defined as the sum of the monetary (market) value of all final goods and services produced in an economy during a period usually one year[13]. Here we must clarify two basic pillars: the first is all goods and services, and the second is the final goods and services. As for the word “all” mentioned in the definition, its meaning includes the inclusion of gross domestic product accounts for all goods and services produced in the economy. Industrial and agricultural products produced in the economy are included in the accounts. Home rental services, banking, tourism, and medical services are recorded in the gross domestic product[14]. There are three ways to calculate the GDP itself:

A – Expenditure method: It represents the total spending on goods and services produced by society during a certain period of time.

B – The method of production achieved in the economic sectors that make up the economy: which are the agricultural sector, the industrial sector, the petroleum sector, the electricity sector, the water sector, the mining sector, the transportation sector, and the government sector.

C – The income method: that is, the sum of the elements of production, which, according to economic theory, is represented by the return on the labor element (wages and salaries), the return on the land and natural resources element (rents and rents), and the return on the organization element (profits)[15]. The economic growth rate is calculated using the gross domestic product by following one of the three aforementioned methods, then comparing it with the output of the previous period and calculating its growth rate, which is called the economic growth rate. Average real per capita income: Per-Capital Income: The average per capita income is considered one of the most accurate standards when measuring the level of economic progress of countries. It is defined as: the amount of continuous real increase achieved in the average per capita income. The reason for this is that if you take the mere increase in the national product as a criterion for growth, the national product may increase without the average per capita income increasing in the event that the rate of increase in population exceeds the rate of increase in national product, thus leading to a decrease in the rate of per capita income, or when the rate of increase equals The increase in population increases with the rate of increase in the gross national product, which keeps the per capita income constant. Economic growth is calculated through this indicator using what is called the simple growth rate, which measures the rate of change in the average real per capita income from one year to another, using the equation that takes the following mathematical formula:

Growth rate = real income per capita for the current period – real income per capita for the previous period/real income per capita for the previous period x 100

Third: Economic growth in Sudan

Sudan’s economy consists of three main economic sectors: agriculture (agriculture, forestry, livestock and fisheries), industry (oil, mining and quarrying, manufacturing and manual industries, electricity and water), services including (building and construction services, trade, hotels and restaurants, transport and communications, Transfer, insurance, real estate, business services, social services, financial institution services, government services, private non-profit services, import duties).

To clarify, we can discuss the situation of each of the three sectors:

1 – The agricultural sector: Before the production and export of oil in 1999, its contribution amounted to 98% of the country’s foreign currency revenues[16]. The agricultural sector also witnessed a decline in its contribution rates after it had maintained its lead among other sectors during the period (1992-2007), as its contribution to the gross domestic product during the period under study ranged between 33.9% in 1992, and 28.2% in 2018, with an average Contribution amounted to 38.2%. It is also noted from the table that economic growth rates increased during the nineties due to increased growth in the agricultural sector, through the focus of the tripartite economic reform program on agricultural development and directing 50% of funding to the agricultural sector. It is noted that there is fluctuation in the overall economic performance in Sudan, as it witnessed a slowdown during the years 1998 and 1999 due to the repercussions of the global financial crisis. It also witnessed stability during the period 2001-2007 due to the entry of the oil sector into revenues.

2 – Industrial sector: The industrial sector witnessed a continuous increase until 2007, with an average contribution of 21.7%. The development of its contribution to the GDP is due to the emergence of oil and its exploitation, the inclusion of its revenues within the state’s general budget since 1999, and the accompanying growth and development in the services sector of communications, roads and electricity. It is noted from the table that its contribution rates have begun to decrease in recent years due to the decline in global oil prices on the one hand and the secession of the state of South Sudan in the year 2011 and its resulting effects on the oil sector and thus the industry sector.

3 – Services sector: From the table above we find that the percentages of the services sector’s contribution to the GDP, despite the continuous decline it witnessed until 2007, witnessed a qualitative boom during the following years with an average contribution of 40.1%, which enabled it to lead the sectors that make up the Sudanese economy during the years of study.

The third axis

Analysis and discussion , Conclusion

Model equations :

The model consists of two equations:

Investment gap: Saving is a function of idle capacity, and the production of raw materials increases the gap due to the lack of resulting saving. Production is affected by natural conditions, and the ratio of investment to real domestic product. The higher the ratio, the smaller the gap unless this is not accompanied by an increase in saving.

Import gap: Exports are a function of terms of trade, the real exchange rate, and investment. It is expected that the positive terms of international exchange will be in favor of exports and a discount on imports and thus lead to narrowing the gap. As for the real exchange rate, the higher the gap narrows, and so does investment, which leads to an increase in exports and the substitution of imports, which works to bridge the gap.

GAP1 = Savings and investment gap

GAP2 = Export and Import gap

URG = Unused energy

PRM = Production of raw materials

CAP = Capital productivity

Ut = Random error

1 , 2  = Constant

 ,  ,   = Coefficients

Model Estimation :

1- Investment-saving gap function :

2-Import-export gap function :

3-Gaps function:

Interpretation and discussion:

The Sudanese economy suffers from distortions in the economic and production sectors, poor exploitation of available resources, low productivity, lack of individual savings, increasing consumption, high inflation, non-exploitation of resources, inflation of public debt due to non-fulfillment of conditions, American sanctions imposed on Sudan politically and economically, and mismanagement. Successive governments lost the state’s resources, and therefore domestic savings became insufficient to finance investment, which led to the creation of a gap (investment – saving). To reduce the difference in this gap, external financing must be obtained, and thus the foreign trade gap (exports – imports) arises due to the weak lack of production, which leads to Decrease in exports.

The first equation shows the effect of unused energy, raw materials production, and capital productivity on the internal gap. We find that all independent variables have a negative effect, and this is consistent with economic theory, which has proven that every increase in the values of any of these variables (unused energy, raw materials production, and productivity Capital) must lead to reducing the size of the internal gap (the savings and investment gap), as the more unused energy increases by (1%), it leads to a reduction in the difference between saving and investment by (28%) and the more the production of raw materials increases by (1%). It leads to reducing the difference between saving and investment by (56%), and whenever capital productivity increases by (1%), it leads to reducing the difference between saving and investment by (49%.(

The coefficient of determination shows that (81%)  of the changes that occur in the internal gap are caused by unused energy, production of raw materials, and capital productivity.

The second equation explains the impact of the terms of trade, the real exchange rate, and investment on the external gap. We find that all of these independent variables have a positive impact on the exports and imports gap, and this is consistent with the economic theory that has proven that every increase in the values of any of these variables (terms of trade The real exchange rate and investment) must lead to reducing the size of the external gap (exports and imports), as the more the terms of trade increase by (1%) lead to reducing the difference between exports and imports by (27%) and the more the real exchange rate increases. By (1%), it leads to reducing the difference between saving and investment by (44%), and whenever investment increases by (1%), it leads to reducing the difference between saving and investment by (21%).

The coefficient of determination shows that (67%) of the changes that occur in the external gap are caused by the terms of trade, the real exchange rate, and investment.

The third equation explains the effect of the internal resources gap on the external trade gap. We find that the internal resources gap has a positive effect in terms of signal, and this is consistent with the economic theory that has proven that increasing the widening of the internal resources gap will lead to an increase in the widening of the external resources gap, as the more the internal gap increases by (1%) will lead to an increase in the external gap by (82%(.

The coefficient of determination shows that (98%) of the changes that occur in the external gap are caused by the foreign trade gap.

We note that the probability values of the t-test corresponding to the model parameters in the three equations are less than (0.05) and there is no autocorrelation problem. Therefore, the models are acceptable in terms of statistical standards.

The Harrod-Domar model in development planning is characterized by the fact that if the foreign exchange gap dominates, borrowing from the outside world supports the country’s foreign exchange, and without it, it is not possible to benefit from all domestic saving because actual growth is restricted by the lack of necessary imports.

Conclusion

The study concluded that the Harrod-Domar model emphasizes the role of imports and foreign exchange in the development process and that the variables of unused energy, production of raw materials and capital productivity led to a reduction in the gap (savings – investment) during the study period. The study also proved that the variables of the real exchange rate and Investment and terms of trade led to reducing the size of the external gap (exports and imports). The study concluded that there is a significant impact of the internal resources gap on the external resources gap. To avoid wasting foreign exchange, ways must be found to raise the savings rate or capital productivity, after knowing the size of The larger gap: This gap must be filled in through foreign borrowing. The import-export gap will decrease provided that exports increase at a faster rate than national income.

References

1. Abdul Wahab Othman Sheikh Musa (2001) “Methodology of Economic Reform in Sudan,” Al-Amlah Press Company, first edition, p. 116
2. Abdul-Azim Saleh Saeed Baathman (2006) “Measures of the development effort necessary to eliminate the development gap in Islamic countries” Unpublished doctoral dissertation, Umm Al-Qura University, Kingdom of Saudi Arabia
3. Al-Zubair Bashir Taha and Hamid Hussein Muhammad (2005), Between Technology and Development, Al-Waad Al-Haqq Publications Series, Issue 52, National Center for Media Production, Khartoum, p. 50
4. Ashwaq Bin Qaddour, The Development of the Financial and Economic System, Dar Al-Rabah for Publishing and, Amman, Jordan, 2013, p. 63.

1. Easterley W (2001) “The Elusive Quest for Growth Economists Adventures and Misadventures in the Tropics” The MIT Press

6. Gamal mohamed syam , Estimating the Investments Required for the Development Plan and the Resource Gap Using the Harrod-Domar Model 1990-2016 , Journal of Agricultural Economics, Mansoura University , 2018
7. Geerdink G C& P.J. Stauvermann (2005) “International Capital Mobility in a Harrod – Domar Model”
8. Ishaq Abkar Abdullah, Analysis of the Impact of Stock Market Performance on Economic Growth Rates, unpublished doctoral thesis, Sudan University of Science and Technology, Sudan, 2018, p. 91.

1. K.H .GHALI, Government Size and Economic Growth: Evidence from

10. Khalaf Allah Ahmad Muhammad Arabi (2009), “Economic Models,” J-Town Press, first edition, p. 58.
11. Khaled Wassef and Ahmed Al-Rifai, Principles of Macroeconomics between Theory and Practice, Wael Publishing House, 7th edition, Amman, Jordan, 2014, p. 107.
12. Muhammad Fawzi Abu Al-Saud, Introduction to Macroeconomics, Alexandria University, 2004, pp. 6-12.
13. Muhammad Medhat Mustafa, Suhair Abdel Zaher, Mathematical Models for Planning and Economic Development, Alexandria, 1999, p. 132.

1. Multivariate Cointegration Analysis, Applied Economic, Vol.31, 1998,

15. Mustafa Ahmed Hamed Radwan, Competitiveness as a mechanism of economic globalization and its role in supporting growth and development efforts in general, University Publishing House, Egypt, 2001, p. 156.

1. Annual reports – Central Bank of Sudan
2. Reports of the Sudanese Central Bureau of Statistics
3. https://www.alukah.net/culture
4. https://fastercapital.com/arabpreneur

[1] Gamal mohamed syam , Estimating the Investments Required for the Development Plan and the Resource Gap Using the Harrod-Domar Model 1990-2016 , Journal of Agricultural Economics and Social Sciences, Mansoura University , 2018

[2] Abdul-Azim Saleh Saeed Baathman (2006 AD) “Measures of the development effort necessary to eliminate the development gap in Islamic countries” Unpublished doctoral dissertation, Umm Al-Qura University, Kingdom of Saudi Arabia

[3]? Geerdink G C& P.J. Stauvermann (2005) “International Capital Mobility in a Harrod – Domar Model”

[4] Khalaf Allah Ahmad Muhammad Arabi (2009), “Economic Models,” J-Town Press, first edition, p. 58.

[5] K.H .GHALI, Government Size and Economic Growth: Evidence from

Multivariate Cointegration Analysis, Applied Economic, Vol.31, 1998,

p975-987.

[6] https://www.alukah.net/culture

[7] Abdul Wahab Othman Sheikh Musa (2001 AD) “Methodology of Economic Reform in Sudan,” Al-Amlah Press Company, first edition, p. 116

[8] Muhammad Medhat Mustafa, Suhair Abdel Zaher, Mathematical Models for Planning and Economic Development, Alexandria, 1999, p. 132.

[9] Easterley W (2001) “The Elusive Quest for Growth Economists Adventures and Misadventures in the Tropics” The MIT Press

[10] https://fastercapital.com/arabpreneur

[11] Ashwaq Bin Qaddour, The Development of the Financial and Economic System, Dar Al-Rabah for Publishing and Distribution, Amman, Jordan, 2013, p. 63.

[12] Mustafa Ahmed Hamed Radwan, Competitiveness as a mechanism of economic globalization and its role in supporting growth and development efforts in general, University Publishing House, Egypt, 2001, p. 156.

[13] Ishaq Abkar Abdullah, Analysis of the Impact of Stock Market Performance on Economic Growth Rates, unpublished doctoral thesis, Sudan University of Science and Technology, Sudan, 2018, p. 91.

[14] Khaled Wassef and Ahmed Al-Rifai, Principles of Macroeconomics between Theory and Practice, Wael Publishing House, 7th edition, Amman, Jordan, 2014, p. 107.

[15] Muhammad Fawzi Abu Al-Saud, Introduction to Macroeconomics, Alexandria University, 2004, pp. 6-12.

[16] Al-Zubair Bashir Taha and Hamid Hussein Muhammad (2005), Between Technology and Development, Al-Waad Al-Haqq Publications Series, Issue 52, National Center for Media Production, Khartoum, p. 50