This paper formulates Rosenberg's (1982) "learning by using" as a stochastic process. The producer of machines learns from the experience of users. Due to this learning, the quality of machines improves over time. It turns out that the process of this improvement approximately takes an...

This paper examines the causes of the observed increase in the average unemployment duration over the past thirty years. First we analyze if changes in the demographic com- position of the U.S. labor force can explain this increase. In particular, we examine how much of the observed change can...

This paper reconsiders the cost of business cycles under market incompleteness. Primarily, we focus on the heterogeneity in the cost among different skill groups. Unskilled workers are subject to a much larger risk of unemployment during recessions than are skilled workers. Moreover, unskilled...