“Dewey Defeats Truman”: Be Aware of Data Revisions
By Dennis J. Fixler, Ryan Greenaway-McGrevy and Bruce T. Grimm, Survey of Current Business, July, 2011
Gross domestic product (GDP) and gross domestic income (GDI) are the two featured measures of the National Income and Product Accounts (NIPAs). Measuring the accuracy of national accounts estimates is a long-standing challenge for three main reasons. One, the early GDP and GDI estimates are based on partial data. Two, the source data come from a mix of survey, tax, and other business and administrative data; these source data are subject to a mix of sampling and nonsampling errors. Three, the national accounts are regularly revised to reflect the changes in the economic concepts and methods necessary for these accounts to provide a picture of the evolving U.S. economy that is relevant and accurate for today’s economy.