Labor mobility may be caused by shifts in the derived demand for labor on the part of firms or s ectors, or it may be caused by mismatches between workers and their j obs. Both reasons may be important, and this paper merges them into o ne model. It explores the consequences for (1) wage-tenure...

This paper explores a model of innovation and spatial co mpetition over time. A key implication of the paper is that firms' size is posit ively autocorrelated across time. The mechanism that generates this persistence works only in heterogenous product markets and is based on the idea that...

I estimate a model in which new technology entails random adjustment needs. Rapid adjustments may cause measured productivity to decline. The slow-downs persist because adjustment is costly, and hence protracted. The model explains both the “steepness” and the “deepness” asymmetry of...

Motivated by the observed rise in the trade of technology, I analyse how technology would spread in a frictionless market. In such a world, low-skilled agents prefer to use old technology because it costs less; their skills do not justify the use of frontier technology. The model generates a...

This paper analyzes a decentralized process for the diffusion of knowledge. In equilibrium, the economy converges from an initial distribution of knowledge over agents to the steady-state distribution, which is unique. Because of the public good aspect of information, too little learning takes...

Motivated by the observed rise in the trade of technology, I analyse how technology would spread in a frictionless market. In such a world, low-skilled agents prefer to use old technology because it costs less; their skills do not justify the use of frontier technology. The model generates a...

I estimate a model in which new technology entails random adjustment needs. Rapid adjustments may cause measured productivity to decline. The slow-downs persist because adjustment is costly, and hence protracted. The model explains both the "steepness" and the "deepness" asymmetry of cycles....