Knowledge that Transforms

The authors regress young adult wages on current age and the score of a basic skills test that was administered over ten years earlier, when respondents were preparing to leave high school and embark on work careers or postsecondary education. Controlling for this one measure of premarket skill greatly reduces the measured black-white wage gap for young adults. The authors' results suggest that the black-white wage gap primarily reflects a black-white skill gap that exists before young men and women enter the labor market. This skill gap in part reflects measured black-white differences in wealth and family background.

A hedonic analysis of principal-agent employment contracts is developed in which workers and employers exchange labor services and contractual payment patterns. Within this framework, tests of alternative hypotheses are formulated and applied to contract data from a unique household-level survey of economic activity in rural China in 1935. The results indicate that credit market constraints motivated workers' and employers' contract choices, that shirking by workers rather than by employers was the dominant incentive issue, that reputational concerns rather than threats of termination were the key worker-disciplining device, and, finally, that the contract's third party acted as an enforcement device rather than as a matchmaker. Subject to the availability of matched agent-principal data, this structural approach to modeling agency relationships can also be used in contemporary settings.

Core theory is a powerful tool to find competitive market-clearing prices. A familiar economic setting shows this, beginning with a single commodity produced using many factors of production and ending with the general case of many outputs and inputs. The analysis describes when the market has a core. When it has no core, there is a least upper bound on the payment each firm that does not participate in a central market must make that serves as an inducement to restore the core. Since each firm can avoid this penalty by trading in the central market, the result is market-clearing prices that can support an efficient equilibrium.

Under a progressive income tax, conventional wisdom is that taxing individuals rather than households is preferred from an efficiency point of view. The reason is that secondary workers, whose labor supply elasticity is high, will be taxed at a lower marginal rate than primary workers, whose labor supply elasticity is low. Here, we argue that once household production is taken into account, things are more complicated since tax design should also not distort the input of family members' time in household production. Factor input distortions as well as Ramsey considerations thus need to enter the choice of the tax unit. We provide a numerical example of an economy for which a move from an individual to a household basis in the income tax can be efficiency improving. We then use a general equilibrium model, parameterized using Australian tax rates and data, whose results clearly show that welfare gains can occur under changes from an individual to a household basis for an existing income tax. Our results thus challenge conventional wisdom and suggest that household unit taxation deserves more sympathetic consideration than is currently the case.

A recent empirical literature has shaken economists' confidence in the value of aggregate (industry-level) data to illuminate production relationships. But the statistical finding "you cannot aggregate," however well documented, is not an economic explanation. Plant-level relationships do aggregate in Depression-era blast furnace operations despite the presence of very substantial interplant heterogeneity, the most common economic cause of nonaggregability. The economic explanation of this lies in poor short-run substitutability of one plant's output for another's. Substitutability determines the importance of composition effects in understanding aggregate time series, constrains the potential cleansing effects of recessions, and therefore influences industry evolution quite broadly.