A human capital model is specified to explain the skill composition of
US immigration. A unique set of panel data (57 source countries and 1
5 annual observations) and a methodology not previously used to study
a demographic phenomenon are employed to estimate the model. Coefficie
nts on time-invariant variables are recovered by means of the Hausman-
Taylor instrumental variable procedure, which yields considerably diff
erent results than the generalized least squares model.