Inventories and Backlogs: An Analysis of The Business Cycle

这个项目涉及一个重要而有趣的主题，即 生产库存和积压的决定因素。 多年 在经济研究中，人们认识到， 在商业周期的变化中发挥核心作用。 即使 季度库存投资水平通常小于1 %的国民生产总值，库存投资的变化往往是重要的， 周期性转折点 事实上，经验证据表明， 存货投资的变化占了近一半 第二次世界大战后八个国家中的大部分国家的商业活动的变化 美国经济衰退的数据在二战前是有限的， 但有迹象表明，同样的关系也存在。 因此，分析 库存的变化可能是预测大范围变化的好方法 在商业活动中。 尽管了解企业积累的原因显然很重要 库存，几乎没有明确的证据表明，企业是否 避免生产成本或销售的不可预见的波动， 当他们增加库存时，最终产品。 此外，企业可以 通过积累积压的订单来实现同样的目标。 因此 最常用于研究库存积累的模型，即 生产平滑模型本身就有缺陷。 这个项目 从企业规避的角度研究生产库存 积压订单的成本。 这些成本一般会更高 而不是简单地持有库存，因为 积压订单会导致客户关系恶化。 从技术上讲，韦斯特教授估计结构模型，以测试 积压成本在数字上和统计上是否显著。 假设生产滞后，如果出现以下情况， 在每个生产周期开始时，订单超过生产。 他还对非线性模型进行随机数值模拟， 解释所观察到的关于清单的事实，特别是 该模型预测，负面需求冲击，即衰退， 导致后世界观察到的那种库存清算 二战时期。

This project concerns an important and interesting topic, namely the determinants of production inventories and backlogs. For many years there has been in economic research the realization that inventories play a central role in changes in the business cycle. Even though the level of quarterly inventory investment is, typically, less than one percent of GNP, changes in inventory investment often are important at cyclical turning points. In fact, empirical evidence shows that changes in inventory investment account for nearly one half the total change in business activity for most of the eight post- World War II recessions in the U.S. Data is limited for the pre-World War II era, but indications are that the same relationship holds. Thus analyzing changes in inventories might be a good method to predict wide shifts in business activity. In spite of the obvious importance of knowing why firms accumulate inventories, there is little unambiguous evidence as to whether firms are avoiding unforeseen fluctuations in production costs or in sales of final products when they increase inventories. In addition, firms can accomplish the same goals by accumulating backlogs of orders. Thus the models most often used to study inventory accumulation, namely the production smoothing models, are inherently flawed. This project studies production inventories from the standpoint of firms' avoiding the costs of backlog orders. These costs can in general be greater than those of simply holding inventories, since having unfilled backlog orders incurs bad customer relations. Technically, Professor West estimates structural models to test whether backlog costs are numerically and statistically significant. A production lag is assumed, and a within period backlog occurs if orders exceed production at the beginning of each production period. He also does stochastic numerical simulations of the nonlinear model, to explain the observed facts about inventories, in particular whether the model predicts that negative demand shocks, that is recessions, induce inventory liquidations of the sort observed in the post-World War II period.