"In a recent paper, Ottaviano and Peri (2007a) report evidence that immigrant and native workers are not perfect substitutes within narrowly defined skill groups. The resulting complementarities have important policy implications because immigration may then raise the wage of many native-born...

"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...