While the employment effects of minimum wages are usually reported to be small (suggesting low substitutability between skill types), direct estimates suggest a much larger degree of substitutability. This paper argues that this paradox is largely due to a bias induced by the aggregation of...

I apply Ricardo’s principle of comparative advantage to a theory of factor substitutability in a model with a continuum of worker and job types. Highly skilled workers have a comparative advantage in complex jobs. The model satisfies the distance-dependent elasticity of substitution (DIDES)...

The Portuguese economy has been characterised by modernisation sincethe post-war period. Lisbon and the Tagus Valley is a centre of thisprocess. Hence, this region faces a high demand for highly skilledlabour. This paper analyses rates of return on human capital in theregion of Lisbon and in the...