Reassessing the empirical validity of the human-capital augmented neoclassical growth model

We reassess Mankiw, Romer and Well's [MRW] version of the Solow model using, as did MRW, cross-sectional data to estimate the steady-state equation governing income per capita levels. The model fails in two critical areas. First, plausible factor shares obtained by MRW are not robust to the substitution of two measures of human capital that are more precise than the secondary school enrollment rates used by MRW. Second, the null hypothesis of an exogenous and identical level of technology in all countries is rejected. We also explain why the Solow model performed well despite the above shortcomings.