Lewis set out the dual sector model in his 1954 publication, "Economic Development with Unlimited Supplies of Labour."
Lewis' model seeks to provide a framework for understanding how relatively poor countries can develop economically. It begins by assuming that one of the characteristics shared by poor countries is that their economies tend to consist largely of "subsistence sectors" in which the supply of labour is very large and the amount of capital invested per worker is very low.
The Lewis model describes a path whereby a developing economy can foster the growth of a new "capitalist sector," which will employ a growing share of the excess labour available from the subsistence sector. Over time, this capitalist sector can come to eclipse the subsistence sector, causing the overall economy to grow.
Like all economic theories, the Lewis model relies on simplifying assumptions to make its argument clear. Therefore, the Lewis model will never be perfectly applicable to reality. Nevertheless, it has been widely praised and used by economists
interested in how developing economies can escape from poverty and produce wealth. For example, many economists
have used the Lewis model as a framework for explaining the extraordinary economic development that China has achieved in recent decades.
Early life and education of Sir Lewis
Sir Lewis was born on January 23, 1915, in the Caribbean island of St Lucia. His parents, both school teachers, were immigrants from Antigua. He complete his school curriculum at the age of 14 and went to work as a clerk in the civil service. After graduating, Lewis’ initial career choice was to become an engineer. He made the eventual switch to economics because the governments and companies of the West Indies, such as Saint Lucia, refused to hire blacks. In 1932, he won a government scholarship and went on to study at the London School of Economics. He was the first black individual to ever gain acceptance at LSE.
Sir Arthur Lewis' life as a lecturer
After gaining his Bachelor of Science degree in 1937 and a PhD degree in 1940 at the LSE, Lewis worked as a member of the staff at the LSE until 1948. After his brief stint at LSE, he was selected as a lecturer at the University of Manchester, and moved there with his family. He taught at Manchester until 1957. In 1963, he was also appointed a University Professor at Princeton University and moved to the United States. Lewis worked at Princeton for the next two decades, teaching generations of students until his retirement in 1983.
Sir Lewis as Economic Advisor
Lewis served as an economic advisor to numerous African and Caribbean governments, namely - Nigeria, Ghana, Trinidad and Tobago, Jamaica and Barbados.
When Ghana gained independence in 1957, its government appointed Lewis as their first economic advisor. He helped draw up its first Five-Year Development Plan (1959–63). In 1959 Lewis returned to the Caribbean region when appointed Vice Chancellor of the University of the West Indies.
In honour of his lifelong achievements, the British government knighted W Arthur Lewis in 1963.