Labor outflows and labor inflows in Puerto Rico2007

"Although a sizable fraction of the Puerto Rican-born population moved to the United States, the island also received large inflows of persons born outside Puerto Rico. Hence Puerto Rico provides a unique setting for examining how labor inflows and outflows coexist, and measuring the mirror-image wage impact of these flows. The study yields two findings. First, the skills of the out-migrants differ from those of the in-migrants. Puerto Rico attracts high-skill in-migrants and exports low-skill workers. Second, the two flows have opposing effects on wages: in-migrants lower the wage of competing workers and out-migrants increase the wage"--National Bureau of Economic Research web site.