Abstract: Objective : The paper is to draw lessons from theoretical and empirical research and also critically examine the mainstream theoretical model of migration to propose an alternative framework that presents migrants into the city not as nuisance, but as important contributors to productivity and growth for the economy as a whole. Methodology : It is a review article which focuses on the existing literature on migration in Classical Economics, Urban Economics, New Growth Theory and New Economic Geography. Findings : The paper argues that when migration is associated with positive externalities in cities, a strong case exists for accommodating migrants in urban areas subject to appropriate policies for urban planning and development incentivized by the national government duly involving the city government. The findings state that when positive externalities of cities are considered, the conclusions from the theories of over-urbanization and over-migration as presented by models such as Harris-Todaro model will need to be drastically modified. Thus, there will be a need to have a positive view of migration calling for effort optimize the contribution of migrants to cities by taking measures to provide them affordable housing, workplaces, basic services, security of tenure, etc. This should be possible by harnessing the benefits of agglomeration and knowledge externalities in cities and using them as resource. Application : The paper can open new research avenues on how an increasing number of migrants can be adapted into the cities by bringing the paradigm shifts in the planning process of the urban centers. The paper also provides the in depth analysis of the varying positions of learners and policy maker over the decades about rural urban migration which can help in systematic study of migrants and their conditions in the cities.

Abstract: I analyze the welfare effects of a policy of modern sector enlargement (MSENL), and a policy of increasing the efficiency of on-the-job search from the urban informal sector (IEOS) in a generalized Harris-Todaro model. I show that MSENL causes a Lorenz worsening of the income distribution and IEOS causes a Lorenz improvement. In a rare direct application of the Atkinson theorem, I conclude that MSENL decreases social welfare and IEOS increases social welfare for all anonymous, increasing and Schur-concave social welfare functions.