Inventories In National Economies

This book introduces a new approach in the field of macroeconomic inventory studies: the use of multivariate statistics to evaluate long-term characteristics of inventory investments in developed countries. By analyzing a 44-year period series of annual inventory change in percentage of GDP in a set of OECD countries, disclosing their relationship to growth, industry structure and alternative uses of GDP (fixed capital investments, foreign trade and consumption), it fills a gap in the economic literature. It is generally accepted that inventories play an important role in all levels of the economy. However, while there is extensive literature on micro- (and even item-) level inventory problems, macroeconomic inventory studies are scarce. Both the long-term processes of inventory formation and their correlation with other macroeconomic factors provide interesting conclusions about economic changes and policies in our immediate past, and present important insights for the future.

The principles underlying the recording of changes in inventories are explained in the System of National Accounts, 1993 (1993 SNA), but operational guidelines on their measurement are lacking. This paper elaborates specific statistical techniques and their underlying assumptions for calculating changes in inventories and holding gains when only data on stocks of inventories are available. Several data situations are considered. The authors propose methods for measuring changes in inventories that meet the 1993 SNA principles. The paper also explores possibilities for implementing the proposed improvements and explains the interpretation of data on changes in inventories.

The authors find that raw materials inventories in the manufacturing sector in the 1970s and 1980s were two to three times higher in developing countries than in the United States, despite the fact that in most developing countries real interest rates were at least twice as high. Those significantly high levels of inventories are a burden and an obstacle to country competitiveness and need to be addressed. Poor infrastructure and ineffective regulation, as well as deficiencies in market development, rather than the traditional factors used in inventory models (such as interest rates and uncertainty), are the main determinants and explain these differences. Cross-country estimations show that a one standard deviation worsening of infrastructure increases raw materials inventories by 11 percent to 37 percent, and a one standard deviation worsening of markets increases raw materials inventories by 18 percent to 37 percent. These findings are robust across a number of different proxies and specifications, including an industry-level specification that controls for fixed country effects.

The principles underlying the recording of changes in inventories are explained in the System of National Accounts, 1993 (1993 SNA), but operational guidelines on their measurement are lacking. This paper elaborates specific statistical techniques and their underlying assumptions for calculating changes in inventories and holding gains when only data on stocks of inventories are available. Several data situations are considered. The authors propose methods for measuring changes in inventories that meet the 1993 SNA principles. The paper also explores possibilities for implementing the proposed improvements and explains the interpretation of data on changes in inventories.

This study falls into two parts. Part I contains a theoretical analysis of the relation of inventories and inventory fluctuations to the business cycle. It begins with a brief survey of the treatment of inventories in the literature of business cycles. Then a theoretical model of the economic system is developed as a basis for judging the nature and importance of inventory fluctuations in the economy. Part II is a study of inventory fluctuations in Canada over the period from 1918 to 1950 and provides some inductive verification of the preceding theoretical argument. The behaviour of inventories in ten important manufacturing industries is analysed in detail. This part also contains analysis of the movement of total inventories and of the behaviour of inventories in the main industrial subdivisions of the economy. Finally a brief chapter relates these findings to the theoretical analysis of Part I. Canadian Studies in Economics, No. 10.