We estimate the elasticity of substitution between high-skill and low-skill workers using panel data from 32 countries during 1970–2015. Most existing estimates, which are based only on US microdata, find a value close to 1.6. We bring international data together with a theory-informed macro-approach to provide new evidence on this important macroeconomic parameter. Using the macro-approach, we find that the elasticity of substitution between tertiary-educated workers and those with lower education levels falls between 1.7 and 2.6, which is higher than previous estimates but within a plausible range. In some specifications, estimated elasticity is above the value required for strong skill-bias of technology, suggesting strong skill-bias is possible.

Even for the standard skill-biased technological change (SBTC) literature, the generic rise in the skill premium in the face of the relative increase in skilled workers since the 1980s seems a little puzzling. We develop a general equilibrium SBTC growth model that allows the dominance of either the price channel or the market-size channel mechanism through which network spillovers affect the technological-knowledge bias and, thus, the paths of intra-country wage inequality. The proposed mechanisms can accommodate facts not explained by the earlier literature.

I develop an assignment model to quantify, in a unified framework, the causal effects of supply and demand forces on the evolution of the college wage premium in the US economy. Specifically, I quantify the relative contributions of four different forces: (i) a within-sector non-neutral technological change, (ii) the creation of new high-skill services/sectors, (iii) polarizing product demand shifts, and (iv) shifts in the relative supply of skilled labor. The model considers endogenous human capital accumulation. I find that positive supply shifts completely explain the fall of the skill premium during the period 1970–1980. Demand forces play a major role in the post-1980 period, when the skill premium rises. Among the demand forces, the results show an increasing contribution of polarizing product demand shifts over the decades. On the other hand, the effect of the within-sector non-neutral technological change is more important in the earlier decades of the post-1980 period.

This paper analyzes optimal capital and labor income taxation for households differentiated by labor skill, income, and wealth, under a balanced government budget, over the business cycle. A model incorporating capital–skill complementarity in production and differential access to labor and capital markets is developed to capture the cyclical characteristics of the US economy, as well as the empirical observations on wage (skill premium) and wealth inequality. We find that optimal taxes for middle-income households are more volatile than the remaining taxes. Moreover, the government re-allocates the total tax burden in bad times so that the share of total tax revenue paid by middle-income households rises. This share also rises for low-income households but by significantly less, whereas the tax share for skilled households falls.

For the United States, the supply and wages of skilled labor relative to those of unskilled labor have grown over the postwar period. The literature has tended to explain this through “skill-biased technical change” (SBTC). Empirical work has concentrated around two variants: (1) capital-skill complementarity, (2) skill-augmenting technical change. Our purpose is to nest and discriminate between these two explanations. We do so in the framework of multilevel Constant Elasticity of Substitution (CES) production function, where factors are disaggregated into skilled and unskilled labor, and capital into structures and equipment capital. Using a five-equation system approach and several nesting alternatives, we retrieve estimates of the substitution elasticities and technical changes. Our estimations can produce results in line with capital-skill-complementarity hypothesis. However, those results are outperformed where the only source of the widening skill premium has been skill-augmenting technical change. We also show that the different explanations for SBTC have different implications for projected developments of the premium.

Historically, industrialization has been associated with falling relative returns to skills. This fact is at odds with most unified theories of industrialization, which tend to imply rising skill premia as natural concomitants of economic growth. This paper develops a very simple model of historical growth to help solve this puzzle. Assuming that human capital is both a consumption good and an investment good, the model demonstrates how gradually rising investments in human capital, nonmonotonic fertility rates, and falling skill premia can all be explained within one theory.