Human capital plays an important role in the theory of economic growth, but it has been difficult to measure this abstract concept. We survey the psychological literature on cross-cultural IQ tests, and conclude that modern intelligence tests are well-suited for measuring an important form of a...

I study the consequences of heterogeneity of skills for the design of an optimal unemployment insurance, using a principal-agent set-up with a risk neutral insurer and infinitely lived risk averse agents. Agents, who are characterised by different productivities or skills, are employed by firms...

I show that in a conventional Ramsey model, between one-fourth and one- half of income differences across countries can be explained by a single factor: The steady-state effect of large, persistent differences in national average IQ on worker productivity. These differences in cognitive...

I estimate a life cycle model of consumption choice with unemployment risk. Employed individuals face the risk of losing their job. Unemployed agents receive job random offers of different quality, which they can accept or reject. Following the loss of a job and during unemployment, an agent’s...