Lewis Dual Sector Model and Structural Transformation

W. Arthur Lewis developed the Dual Sector Model in 1954 to explain the economic development of countries with dual economies, where traditional agriculture coexists with modern industrial sectors. His model highlighted the importance of labor transfer from agriculture to industry, emphasizing how this transition could lead to economic growth and development.

In the Lewis model, the traditional sector is characterized by low productivity and is predominantly involved in agriculture and subsistence farming. This sector provides the foundation for economic development, as it employs a significant portion of the labor force while relying on basic techniques and limited capital investment.

In the Lewis model, 'surplus labor' refers to the excess number of workers in the agricultural sector who contribute minimally to output due to their low marginal productivity. This surplus allows for labor transfer to the industrial sector without affecting agricultural output, facilitating economic growth and development.

In the Lewis model, the modern sector is defined by its use of advanced technology and capital-intensive methods, which lead to increased productivity. This efficiency results in higher profits compared to traditional sectors, where labor is often less productive and reliant on subsistence-level income.

In the Lewis model, economic growth primarily occurs through capital accumulation in the modern sector. This process involves transferring surplus labor from the traditional agricultural sector to more productive industrial activities, leading to increased investment, higher productivity, and ultimately, economic expansion. The focus is on developing industries that can drive growth and create jobs.

In the Lewis model, as workers migrate from agriculture to industry, wages in agriculture remain at the subsistence level due to a surplus of labor. This means that even with migration, the supply of labor in agriculture keeps wages stable, preventing any significant increase in earnings for workers, regardless of the sector they are in.

In the Lewis model, the turning point signifies the transition from a dual economy with surplus labor in the agricultural sector to a more developed economy. When surplus labor ends, it indicates that all available labor has been absorbed into the industrial sector, leading to rising wages and a shift towards sustained economic growth and development.

Structural transformation describes the transition of economies from being primarily agricultural to becoming more industrialized and service-oriented. This shift often involves changes in production methods, labor distribution, and economic activities, leading to enhanced productivity and development. Such transformations are crucial for economic growth and modernization.

In the Lewis model, profits generated in the modern sector are reinvested to accumulate capital, which is essential for sustaining economic growth. This reinvestment helps to expand production capacity, improve technology, and enhance productivity, ultimately leading to increased output and higher living standards in the economy.

The original Lewis model assumes an endless supply of labor from the rural sector to the urban sector without considering potential constraints. This leads to unrealistic projections, as it does not account for factors like migration, urbanization limits, or changes in labor availability, which can significantly impact economic growth and development.

In the Lewis model of economic development, the traditional sector is characterized by subsistence agriculture and limited technology. Consequently, the marginal productivity of labor in this sector is considered very low, as additional workers contribute minimally to output. This reflects the surplus labor present, which does not significantly enhance productivity until they transition to more productive sectors.

In the Lewis dual sector model, international trade is not explicitly accounted for, as the focus is primarily on the dynamics between the traditional agricultural sector and the modern industrial sector. The model emphasizes internal factors such as labor migration and capital accumulation, rather than external influences like trade.