Q. The migration model of Todaro and Harris provided an important theoretical critique of the manufacturing-biased import-substitution trade-policy stance. Illustrate.

Answer: The Lewis model provide a rationale for manufacturing-biased import substitution trade policy since the marginal cost of expanding manufactures is close to zero just high enough to induce a worker to migrate from the farm to the city. Though Harris and Todaro identified a significant negative social and economic externality associated with this process namely the problems associated with unplanned and very rapid urbanization combined with rapidly rising expectations of urban migrants.