Training,migration, and regional income disparities

"It is assumed that there are two regions, that production requires both skilled and unskilled labour, and that one region is innately more productive than the other. Workers, who differ in their migration or training costs, make individually rational decisions. In equilibrium the ratio of skilled workers to unskilled workers is always higher in the more productive region. Average incomes differ between regions because regional differences in wage rates are reinforced by regional differences in the structure of employment. The model is also used to analyse the effects of policies intended to equalize the distribution of income."