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 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 1993 SNA represents a major advance in national accounting. While updating and clarifying the 1968 SNA, the 1993 SNA provides the basis for improving compilation of national accounts statistics, promoting integration of economic and related statistics, and enhancing analysis of economic developments. The 1993 SNA deals more clearly with relationships between economic flows (such as production, income, savings, accumulation, and financing) and links between these flows and stocks. At the same time the 1993 SNA reflects the many significant developments that have taken place in financial markets and completes the integration of balance sheets into the system. The 1993 SNA also suggests how satellite accounts (e.g. environmental accounts) and alternative classifications (e.g., through social accounting matrices) an be used to augment the central framework of the system.

This is an update of OECD 2006 "Understanding National Accounts". It contains new data, new chapters and is adapted to the new systems of national accounts, SNA 2008 and ESA 2010.