DP12451 The Human Capital Stock: A Generalized Approach. Comment
Jones (2014) considers development accounting when workers with different schooling are imperfect substitutes. His main result is that, using plausible values for the elasticity of substitution between workers with different educational attainment, measured human capital variation can be boosted to the point that factors of production account for the totality of the variation in income across countries. We show that the amplification of cross-country human capital differences achieved by Jones, and hence his success at removing the unexplained component of income differences, is entirely due to an assumption that the relative wage of skilled workers is solely determined by attributes of workers (once the supply of skilled workers is accounted for). If, as we argue, skill premia are also influenced by technology, institutions, and other features of the economic environment, cross-country differences in human capital as measured by Jones will embed differences in these technological, institutional, and other attributes. As a result, Jones's conclusion that human capital can account for all the variation in income across countries is unwarranted.