lewis model of growth : assumptions , Explanation, Implications and Criticism
Lewis model of growth
Introduction
The Lewis model of growth is a theoretical model that explains how an economy with an unlimited supply of labor can achieve long-term economic growth. The model was first introduced by Israeli economist Moses Abramovitz in 1956, but it has since been refined and expanded by other economists.
The Lewis model is based on the idea that an economy's growth is primarily driven by technological advancements and increases in productivity. It argues that as technology improves, more output can be produced with the same amount of labor. This, in turn, leads to increased economic growth, higher wages, and improved living standards.
In this essay, we will discuss the Lewis model of growth with an unlimited supply of labor. We will provide a detailed explanation of the model and its assumptions, and we will discuss its implications for economic growth.
Assumptions of the Lewis Model
The Levi's model is based on several key assumptions. These assumptions are:
Unlimited supply of labor: The model assumes that the economy has an unlimited supply of labor. This means that there are no constraints on the availability of workers.
Fixed amount of land: The model assumes that the economy has a fixed amount of land. This means that there are no new resources that can be exploited.
Technological progress: The model assumes that there is technological progress in the economy. This means that new technologies are being developed that allow for more efficient production.
Constant returns to scale: The model assumes that there are constant returns to scale. This means that increasing the amount of inputs (such as labor and capital) will result in a proportional increase in output.
No external factors: The model assumes that there are no external factors that can affect the economy, such as wars or natural disasters.
Explanation of the Lewis Model
The Levi's model can be explained using the production function:
Y = F(K, AL)
Where Y is output, K is capital, L is labor, and A is the level of technology. The production function shows how much output can be produced given a certain level of capital, labor, and technology.
The model assumes that labor is abundant and can be hired at a constant wage rate, which means that the cost of labor is fixed. The model also assumes that capital is scarce and can only be increased through investment. The level of technology, A, is assumed to increase over time.
The production function can be rewritten as:
Y/L = F(K/L, A)
This equation shows how much output can be produced per unit of labor. As technology improves (A increases), the amount of output that can be produced per unit of capital and labor (K/L) also increases. This means that the economy can grow without running out of labor.
The model also assumes that there are constant returns to scale. This means that increasing the amount of inputs (such as labor and capital) will result in a proportional increase in output. This assumption is necessary for the model to show that an economy with unlimited labor can achieve long-term economic growth.
Lewis Model of Growth with Unlimited Supply of Labor:
The Lewis model of growth with unlimited supply of labor is a two-sector model in which the economy is divided into two sectors: the traditional agricultural sector and the modern industrial sector. The traditional agricultural sector is characterized by low productivity, low wages, and surplus labor. The modern industrial sector, on the other hand, is characterized by high productivity, high wages, and a shortage of labor.
The basic idea of the Lewis model is that the surplus labor in the traditional agricultural sector can be used to supply labor to the modern industrial sector without affecting the wage rate in the agricultural sector. This is because the supply of labor in the traditional agricultural sector is unlimited, which means that any increase in the demand for labor in the modern industrial sector can be met by an increase in the supply of labor from the traditional agricultural sector.
The process of labor transition from the traditional agricultural sector to the modern industrial sector in the Lewis model can be broken down into three stages:
The Traditional Agricultural Sector:
In the first stage, the economy is dominated by the traditional agricultural sector, which is characterized by low productivity and low wages. The surplus labor in the agricultural sector is not fully employed, which means that there is excess labor available for other sectors of the economy. This surplus labor can be used to supply labor to the modern industrial sector without affecting the wage rate in the agricultural sector.
The Transition Stage:
In the second stage, the modern industrial sector starts to grow, and the demand for labor in this sector increases. As a result, some of the surplus labor in the agricultural sector starts to migrate to the industrial sector. This migration of labor leads to an increase in the productivity of labor in the industrial sector, which in turn leads to an increase in the wage rate in the industrial sector.
The Modern Industrial Sector:
In the third stage, the modern industrial sector becomes the dominant sector in the economy, and the traditional agricultural sector becomes a small and declining sector. The labor market in the industrial sector becomes tight, and the wage rate in this sector increases further. At this stage, the economy has completed the process of labor transition from the traditional agricultural sector to the modern industrial sector.
Implications of the Lewis Model:
The Lewis model has several implications for economic policy in developing countries:
Industrialization:
The Lewis model suggests that industrialization is an important driver of economic growth in developing countries. Industrialization leads to an increase in productivity and wages, which in turn leads to a reduction in poverty and an increase in living standards.
Labor Market Policies:
The Lewis model suggests that labor market policies can play an important role in facilitating the process of labor transition from the traditional agricultural sector to the modern industrial sector. Policies that promote education and training can help workers in the agricultural sector acquire the skills they need to work in the industrial sector. Policies that promote the development of infrastructure, such as roads and transportation, can also facilitate the movement of labor from the agricultural sector to the industrial sector.
Structural Transformation:
The Lewis model suggests that structural transformation is an important driver of economic growth in developing countries. Structural transformation refers to the process of shifting labor and capital from low-productivity sectors to high-productivity sectors. In the Lewis model, the shift from the traditional agricultural sector to the modern industrial sector is an example
Income Inequality:
The Lewis model suggests that the process of labor transition from the traditional agricultural sector to the modern industrial sector can lead to income inequality. The wage rate in the industrial sector is typically higher than the wage rate in the agricultural sector, which means that workers who transition to the industrial sector can experience a significant increase in their income. However, workers who remain in the agricultural sector may not experience the same level of income growth, which can lead to income inequality.
Technological Change:
The Lewis model suggests that technological change is an important driver of economic growth in developing countries. Technological change can lead to an increase in productivity and a reduction in labor requirements in the industrial sector, which can in turn lead to an increase in the demand for labor in other sectors of the economy. Technological change can also facilitate the movement of labor from the agricultural sector to the industrial sector by reducing the skills required to work in the industrial sector.
Urbanization:
The Lewis model suggests that urbanization is an important outcome of the process of labor transition from the traditional agricultural sector to the modern industrial sector. As workers transition from the agricultural sector to the industrial sector, they tend to move from rural areas to urban areas where the industrial sector is located. This process of urbanization can lead to the development of urban areas and the growth of cities.
Export-Led Growth:
The Lewis model suggests that export-led growth can be an effective strategy for developing countries to promote economic growth. Export-led growth involves promoting the production of goods and services for export, which can lead to an increase in foreign exchange earnings and an increase in economic growth. The Lewis model suggests that the modern industrial sector can be a key driver of export-led growth in developing countries.
Criticism of the Lewis Model
The assumption of an unlimited supply of labor is unrealistic The assumption of an unlimited supply of labor is unrealistic as it does not take into account the social and political factors that limit the movement of labor from the agricultural sector to the industrial sector. The movement of labor from the agricultural sector to the industrial sector is not automatic, and it depends on the institutional factors such as the availability of education and training, the existence of labor laws and regulations, the level of unionization, and the role of the state in regulating the labor market.
The model assumes a fixed stock of capital The assumption of a fixed stock of capital is also unrealistic as it does not take into account the role of investment in the growth process. Investment plays a crucial role in economic growth, as it increases the stock of capital and allows for the adoption of new technologies, which can increase productivity and output. The Lewis Model does not take into account the role of investment in the growth process, and this is a significant limitation of the model.
The model assumes perfect competition in the labor market The assumption of perfect competition in the labor market is also unrealistic, as it does not take into account the power asymmetries between employers and employees. In reality, employers have more bargaining power than employees, and this can lead to the exploitation of workers, especially in the absence of labor laws and regulations. The Lewis Model assumes that wages are determined by the marginal product of labor, which is not always the case in reality.
The model does not take into account the role of technology The Lewis Model does not take into account the role of technology in the growth process. Technology is a significant driver of economic growth, as it allows for the adoption of new production techniques, which can increase productivity and output. The Lewis Model assumes a fixed technology, which is a significant limitation of the model.
The model assumes a homogenous labor force The Lewis Model assumes a homogenous labor force, which is not always the case in reality. In reality, the labor force is diverse, with workers having different skills, education levels, and experiences. The model assumes that all workers have the same level of education and skills, which is not the case in reality.
The model does not take into account the impact of external factors The Lewis Model does not take into account the impact of external factors on economic growth. External factors such as political instability, natural disasters, and changes in the global economy can have a significant impact on economic growth. The Lewis Model assumes a closed economy, which is a significant limitation of the model.
The model does not take into account the impact of income inequality The Lewis Model does not take into account the impact of income inequality on the growth process. Income inequality can have a significant impact on economic growth, as it can lead to a concentration of wealth and power in the hands of a few, which can lead to social and political instability. The Lewis Model assumes that all workers are paid the same wage, which is not the case in reality.
The model assumes that the surplus labor in the agricultural sector is unskilled The Lewis Model assumes that the surplus labor in the agricultural sector is unskilled, which is not always the case in reality. In reality, many workers in the agricultural sector have specialized skills and knowledge that may not be transferable to the industrial sector. The Lewis Model assumes that all workers in the agricultural sector can easily shift to the industrial sector, which is not the case in reality.
The model does not take into account the impact of external trade on the growth process The Lewis Model does not take into account the impact of external trade on the growth process. Trade can have a significant impact on economic growth, as it allows for the specialization of production and the exchange of goods and services. The Lewis Model assumes a closed economy, which is a significant limitation of the model.
The model does not take into account the impact of environmental factors on the growth process The Lewis Model does not take into account the impact of environmental factors on the growth process. Environmental factors such as climate change, pollution, and natural resource depletion can have a significant impact on economic growth. The Lewis Model assumes a constant level of natural resources, which is not the case in reality.
Conclusion
The Lewis model of growth with unlimited supply of labor is a theoretical model that explains how an economy can achieve long-term economic growth without running out of labor. The model is based on several key assumptions, including an unlimited supply of labor, fixed amount of land, technological progress, constant returns to scale, and no external factors.
The model has several important implications for economic growth, including the importance of technological progress, investment in capital, the level of education and skills of the labor force, the sustainability of economic growth, the long-term nature of capital accumulation, and the potential for short-term income inequality.
Overall, the Lewis model provides a useful framework for understanding how an economy with unlimited labor can achieve sustained economic growth over the long-term. However, it is important to recognize that the model is based on several simplifying assumptions and may not fully capture the complexities of real-world economies.
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