As part of each comprehensive and annual revision of the NIPA's, BEA publishes a summary description of the principal source data and methods used to prepare the current-dollar and real estimates of gross domestic product. The most recent "Updated Summary NIPA Methodologies" was published in the September 1997 issue of the SURVEY OF CURRENT BUSINESS and is reprinted as an appendix in this article.
BEA has also prepared a series of papers that discuss the concepts that underlie the NIPA's and that present detailed descriptions of the methodologies used to prepare the NIPA estimates./1/ Note, however, that the methodologies described in these papers are subject to periodic improvements, usually as part of the annual and comprehensive revisions of the NIPA estimates. These improvementswhich consist of changes in definitions and in source data, the incorporation of new source data, and the use of new estimating methodsare described in the SURVEY. For example, two major improvements were the shift to gross domestic product as the featured measure of U.S. production and the introduction of a new treatment of government investment./2/
Copies of the following methodology papers are available from the National Technical Information Service (NTIS).
The results of the most recent comprehensive and annual revisions are published in the following SURVEY articles.
The methodological information on the NIPA's is also available on BEA's Web site at "http://www.bea.doc.gov".
1. For information on the methodology used to prepare the national estimates of personal income, which provide the basis for the State estimates of personal income, see State Personal Income, 195993 (Washington, DC: U.S. Government Printing Office, 1995).
2. See "Gross Domestic Product as a Measure of U.S. Production," SURVEY 71 (August 1991): 8; and "Preview of the Comprehensive Revision of the National Income and Product Accounts: Recognition of Government Investment and Incorporation of a New Methodology for Calculating Depreciation," SURVEY 75 (September 1995): 3341.