Inventories and the Business Cycle

This paper examines the relationship between the inventory cycle and the business cycle. It uses both macro-economic data and data from surveys of individual firms’ actual and expected inventory accumulation. It is argued that over the past decade and a half, the amplitude of the inventory cycle has been reduced. This reduction in amplitude reflects the decline in the stocks to sales ratio and the decline in the relative importance of unintended inventory investment. In part, these changes have been made possible by the application of increasingly sophisticated inventory management techniques. The paper also argues that the behaviour of inventories is consistent with demand shocks being a principal source of business cycle fluctuations. This is in contrast to a number of recent papers that have argued that shocks to the cost of production are the driving force of the inventory and output cycles. We find that demand factors dominate cost factors in explaining both expected and unexpected changes in inventory investment.