Identification of the strength of human capital externalities at the aggregate level is still not fully understood. The existing method may yield positive or negative externalities even if wages reflect marginal social products. We propose an approach that yields positive average human capital...

Immigrants may complement native workers, increase productivity, allow specialization by skill in the firm and lower costs. These effects could be beneficial for the firm and increase its productivity and profits. However not all firms use immigrants. Allowing firms to have differential fixed...