A general purpose technology or GPT is a term coined to describe a new method of producing and inventing that is important enough to have a protracted aggregate impact. Electricity and information technology (IT) probably are the two most important GPTs so far. We analyze how the U.S. economy...

We model Moore's Law as efficiency of computer producers that rises as a by-product of their experience. We find that (1) Because computer prices fall much faster than the prices of electricity-driven and diesel-driven capital ever did, growth in the coming decades should be very fast, and that...

Investment of U.S. firms responds asymmetrically to Tobin's Q: investment of established firms -- 'intensive' investment -- reacts negatively to Q whereas investment of new firms -- 'extensive' investment -- responds positively and elastically to Q. This asymmetry, we argue, reflects a...

Proposes a theory that explains why smaller firms have higher and more variable growth rates than larger firms. Relying on employer heterogeneity and market selection to generate patterns of employer growth and failure, the model states that efficient firms grow and survive while inefficient...

We analyze a long-term contracting problem involving common uncertainty about a parameter capturing the productivity of the relationship, and featuring a hidden action for the agent. We develop an approach that works for any utility function when the parameter and noise are normally distributed...

Machines are more expensive in poor countries, and the relation is pronounced. It is hard for a Solow (1956) type of model to explain the relation between machine prices and GDP given that in most countries equipment investment is under 10% of GDP. A stronger relation emerges in a Solow (1959)...

This paper deals with processes that require several complementary inputs subject to improvements in quality. If after a quality upgrade one of these inputs requires a period of learning before it can be used effectively, then in general it will pay to purchase the inputs at different dates --...

We model research as a signal on an unknown parameter of a technology. We distinguish applied from basic research and show that firms in the same industry can optimally choose different research portfolios, and that basic research can seem to have a higher rate of return than applied research,...

In this essay we explore the implications of human capital and search behavior for both the interpersonal and life-cycle structure of inter-firm labor mobility. The economic hypothesis which motivates the analysis is that individual differences in firm-specific complementarities and related...

This paper explores a one-agent Bayesian model of learning by doing and technological choice. To produce output, the agent can choose among various technologies. The beneficial effects of learning by doing are bounded on each technology, and so long-run growth in output can take place only if...