Evolution of technology causes human capital to become obsolete. We study this phenomenon in an overlapping generations setting, assuming it is hard to predict how technology will evolve, and that older workers find updating uneconomic. Among our results is the proposition that (under certain...

The evolution of technology causes human capital to become obsolete. We study this phenomenon in an overlapping generations setting, assuming that technology evolves stochastically and that older workers find updating uneconomic. Experience and learning by doing may offer the old some income...

This paper analyzes the evolution of the distributions of output and employment across firms in U.S. manufacturing industries from 1963 until 1997. The firm size distribution changes significantly as an industry goes through stages of its life-cycle. The evolutions of the employment and output...

This paper analyzes the evolution of the distributions of output and employment across firms in U.S. manufacturing industries from 1963 until 1997. The evolutions of the employment and output distributions differ, but display strong inter-industry regularities, including that the nature of the...

This paper develops and analyzes a macroeconomic model in which aggregate growth and fluctuations arise from the discovery and diffusion of new technologies; there are no exogenous aggregate shocks. The temporal behavior of aggregates is driven by individuals' efforts to innovate and/or make use...

The initial expansionary phase of the business cycle appears to be characterized by what commentators have labelled a puzzling "jobless recovery" phase i.e., rapid growth in productivity (and output) with relatively sluggish expansion in employment. We demonstrate that a jobless recovery is a...

How does competition among economic actors determine the value that each is able to appropriate? We provide a formal, general framework within which this question can be posed and answered, and then provide several results. Chief among them is a condition that is both required for, and...

We analyze a multiple-activity, principal-agent model in which the activities are naturally substitutable for the agent and complementary for the principal. A basic result is that the optimal compensation must cause the agent to view the activities as complements. This complementarity is...

We study the evolution of educational attainment of the 1932-1972 cohorts using a human capital investment model with heterogeneous learning ability. Inter-cohort variation in schooling is driven by changes in skill prices, tuition, and education quality over time, and average learning ability...