The economic analysis of international migration: a generalization

"This note examines and extends the following two propositions: that finite international factor movements are beneficial to the nationals of the destination country but detrimental to those left behind in the source country and that marginal movements do not have such welfare effects. Using some newly developed techniques, the propositions are found to be valid, irrespective of the number of goods and factors, if the economy starts from the autarky position. When only one factor can flow, the gain of the nationals (loss of those left behind) will be positively dependent upon the amount of inflow (outflow). However, if goods trade and/or factor flow are initially present, the propositions are in general not true." (SUMMARY IN FRE)