We introduce firm and worker heterogeneity into a model of innovation-driven endogenous growth. Individuals who differ in ability sort into either a research sector or a manufacturing sector that produces differentiated goods. Each research project generates a new variety of the differentiated...

In this paper we first document inequality trends in wages, hours worked, earnings, consumption, and wealth for Germany from the last twenty years. We generally find that inequality was relatively stable in West Germany until the German unification (which happened politically in 1990 and in our...

In cross-sectional studies, countries with greater income inequality typically exhibit less support for government-led redistribution and greater acceptance of wage inequality (e.g., United States versus Western Europe). If individual nations evolve along this pattern, a vicious cycle could form...

This paper presents new evidence on the rate of return on tangible assets in the United" States, incorporating the recently-revised national accounts as well as new estimates of the" replacement cost of the reproducible physical capital stock. The pretax return on capital in the" nonfinancial...

This paper examines the family income -- college enrollment relationship and the evidence on credit constraints in post-secondary schooling. We distinguish short-run liquidity constraints from the long-term factors that promote cognitive and noncognitive ability. Long-run factors crystallized in...

This paper examines the evolution of the corporate profit base and the relationship between book income and tax income for U.S. corporations over last two decades. The paper demonstrates that this relationship has broken down over the 1990s and has broken down in a manner that is consistent with...

This paper considers the sources of skill formation in a modern economy and emphasizes the importance of both cognitive and noncognitive skills in producing economic and social success and the importance of both formal academic institutions and families and firms as sources of learning. Skill...

This paper is no longer available on-line from the NBER. A revised version of the paper has been published as "Diversification Across Time" in the Journal of Portfolio Management 39 (Winter 2013), pp.73-86.

Demographic change has differential impacts on the welfare of current and future generations. In a simple closed economy, aging -- a relative scarcity of young workers -- increases wages, increasing the welfare of the young. At the same time, population aging will reduce rates of return to...