Cyclical patterns in earnings can arise when contracts between firms and their workers are incomplete, and when workers cannot borrow or lend so as to smooth their consumption. Earnings cycles generate occasional large changes in earnings, consistent with some recent empirical findings. At the...

This paper shows that endogenous cycles can arise when contracts between firms and their customers are incomplete and when products are experience goods. Then firms invest in the quality of their output in order to establish a good reputation. Cycles arise because investment in reputation causes...

Commitment is therefore more valuable when quality is known more precisely. Incentives then are easier to provide because the agent has less room to manipulate the beliefs of the principal. Moreover, in contrast to results under one-period commitment, wage volatility declines as experience...

Cyclical patterns in earnings can arise when contracts between firms and their workers are incomplete, and when workers cannot borrow or lend so as to smooth their consumption. Effort cycles generate occasional large changes in earnings. These large changes are transitory, consistent with recent...

This paper models the product cycle and explains how it relates to world inequality. In the model, both phenomena arise because skilled people have a comparative advantage in making high-tech products. The model can explain up to a 10:1 income differential between people and up to a 7:1...

Until its sales of a product materialize, a firm is a "pre-producer" in the market for that product. That firm may may be a new start-up, or it may already sell other products. Firms that do not succeed in generating sales eventually become discouraged and move on to other activities. When this...

I estimate a model in which new technology entails random adjustment costs. Rapid adjustments may cause productivity slowdowns. These slowdowns last longer when retooling is costly. The model explains why growth-rate disasters are more likely than miracles, and why volatility of growth relates...

This paper studies optimal investment policies when the production function depends on capital of various vintages. In such an environment it is natural to ask whether the firm will invest in old-vintage capital at all. In this paper I derive such a condition. Predictably, investment in old...

Aside from the equilibrium that Hotelling (1931) displayed, his model of non-renewable resources also contains a continuum of bubble equilibria. In all the equilibria the price of the resource rises at the rate of interest. In a bubble equilibrium, however, the consumption of the resource peters...

This paper extends Lucas (1978) to a production economy with two capital goods. It is an RBC model in which each unit of investment requires a new idea, an "option". When options are scarce, new capital is harder to put in place and the value of old capital rises. Thus the stock market and...