Learning and Evolution in Markets Under Uncertainty

这个项目考察了在新产品引入的行业中公司的投资决策。在经济学文献中，新兴产业的某些增长和演化模式已经在理论上进行了假设，并在统计上进行了验证。从新产品的推出开始，有一个“增长时代”，在此期间，现有的公司获得可观的利润，新的生产商进入市场，然后是一个“洗牌期”，当价格和盈利能力下降，一些公司离开市场。最后是一个“成熟时代”，在此期间，价格和企业数量都趋于稳定。先前对许多行业的研究发现，在这三个进化阶段中，市场活动都有共同的模式。例如，在“增长时代”，生产能力以s曲线增长，而产出以递减的速度增长。随着时间的推移，价格以递减的速度下降，每个阶段的长度和不同产品的扩散模式都有很大的差异。本项目运用贝叶斯学习模型研究企业在演进过程中不同阶段的投资决策。这些模型包含了不确定性，通常涉及产品需求、行动与行动回报之间的时间延迟，以及从经验中学习。模型的一般类型包括固定需求的产能扩张、需求变化的产能调整、库存调整和价格设定。这个项目考察了在引入新产品的行业中公司的投资决策。在经济学文献中，新兴产业的某些增长和演化模式已经在理论上进行了假设，并在统计上进行了验证。从新产品的推出开始，有一个“增长时代”，在此期间，现有的公司获得可观的利润，新的生产商进入市场，然后是一个“洗牌期”，当价格和盈利能力下降，一些公司离开市场。最后是一个“成熟时代”，在此期间，价格和企业数量都趋于稳定。这些阶段在蒸汽动力、柴油机车、计算机的采用以及新工业产品的一般横截面中都可以观察到。在行业发展过程中，企业获得了更多关于其经营所在市场的信息，例如对产品的需求，以及同一市场中其他企业的行为。这些增加的信息影响了企业在新生产工艺、产出能力和招聘方面的投资决策。了解产业的演化过程和新技术的传播，有助于提高我们对生产率、研发投资和产业创新的认识。

This project examines the investment decisions of firms in industries where new products are introduced. In the Economics literature, certain patterns of growth and evolution of new industries have been postulated theoretically, and verified statistically. Commencing with the introduction of the new product, there is a "growth era" during which existing firms make substantial profits and new producers enter the market, then follows a "shakeout period" when prices and profitability decrease and some firms leave the market. Finally a "mature era" prevails, during which a stabilization in both prices and the number of firms occurs. Previous studies of many industries have found common patterns of market activity during these three evolutionary stages. For instance, during the "growth era" productive capacity increases following an S-curve whereas output rises at a decreasing rate. Prices decline over time at a decreasing rate, and there is a substantial variance in the length of each stage, and the pattern of diffusion for different products. This project applies Bayesian learning models to study the investment decisions of firms at various stages in the evolutionary process. These models incorporate uncertainty, typically concerning demand for the products, time delays between action and the payoff to that action, and learning from experience. The general types of models include capacity expansion with fixed demand, capacity adjustment with changing demand, inventory adjustment, and price setting. %%% This project examines the investment decisions of firms in industries where new products are introduced. In the Economics literature, certain patterns of growth and evolution of new industries have been postulated theoretically, and verified statistically. Commencing with the introduction of the new product, there is a "growth era" during which existing firms make substantial profits and new producers enter the market, then follows a "shakeout period" when prices and profitability decrease and some firms leave the market. Finally a "mature era" prevails, during which a stabilization in both prices and the number of firms occurs. These stages have been observed in the adoption of steam power, diesel locomotives, computers, and in a general cross-section of new industrial products. During the evolution of the industry, firms gain more information about the market in which they are operating, for example demand for the product, and about the actions of other firms in the same market. This added information influences the firms' decisions concerning investment in new production processes, output capacity, and hiring. Gaining an understanding of the evolutionary process of industries and the diffusion of new technologies holds the promise of increasing our knowledge about productivity, investment in research and development, and industrial innovation.