A Simple Durable Goods Model
分析耐用品特性对生产和消费的影响，发现消费者推迟购买导致的需求囤积，能解释为何产出波动大于销售波动，即使需求冲击是序列独立的。
The durability of a good has two implications. First, it can be stored in inventories by producers. Second, if it provides a stream of services to consumers, consumers may wish to defer purchases to take advantage of price fluctuations. The most significant conclusion is that the stockpiling of demand that results when consumers defer purchases explains why the variance of output exceeds the variance of sales even if demand shocks are serially independent.