The purpose of this paper is to reassess the standard Solow growth model,using a dynamic panel data approach. A new methodology is chosen to deal with this problem. First, unit root tests for individual country time series were run. Second, panel data unit root and cointegration tests were...

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...