This paper examines the role of migration networks in determining self-selection patterns of Mexico-U.S. migration. A simple theoretical framework shows the impact of networks on migration incentives at different education levels and how this affects the composition of migrant skills. Empirically, we find positive or education-neutral selection in communities with weak migrant networks but negative self-selection in communities with stronger networks. This is consistent with high migration costs driving positive or intermediate self-selection, as advocated by Chiquiar and Hanson (2005), and with negative self-selection being driven by lower returns to education in the United States than in Mexico, as advocated by Borjas (1987).

Wage subsidies have long been used by Governments as part of their active labor market policies to generate employment for the disadvantaged or to sustain employment during downturns. The current global financial crisis has seen such policies return to prominence, with many developed nations using such policies to try and reduce lay-offs. Nicholas Kaldor (1936), P. Richard Layard and Stephen Nickell (1980), and Lawrence Katz (1998) lay out the economic arguments for such a policy, and discuss conditions under which a short-term subsidy might have longer-term effects on employment for the targeted individuals.

Why Do Firms in Developing Countries Have Low Productivity? by Nicholas Bloom, Aprajit Mahajan, David McKenzie and John Roberts. Published in volume 100, issue 2, pages 619-23 of American Economic Review, May 2010