An Analysis of the Necessary and Sufficient Conditions for the Migration of Rural Surplus Labor——Based on the Expected Benefit-cost Theory

In combination with the theory of benefit-cost and Todaro Model, on the basis of an analysis of farmers‘expectant benefit and cost for the migration, through studying the collected data, the authors made a comparative analysis of the “local migration” and “long-distance migration” and their income before and after the two different ways of migration.The conclusions are as follows: firstly, the difference between the lowest expected incomes for “local migration” and “long-distance migration” is much more than the cost of “long-distance migration”; secondly, farmers’ lowest expected monthly incomes for “local migration” and “long-distance migration” are respectively 3.42 and 4.80 times their monthly income per capita in the village(excluding the income gained as migrant workers). Those two ratios are just the focus of this paper——the necessary and sufficient conditions for the migration of rural surplus labor, and the two ratios may decrease depending on the economic level of different rural areas.