For each annual update of the AIAs, revisions are made to both current-dollar and real estimates of value added by industry for the last 3 years. Estimates for years prior to the last 3 typically remain unchanged until the next comprehensive revision of the AIAs and the National Income and Product Accounts (NIPAs), upon which the AIAs are based. Of the three components of value added -- compensation of employees, taxes on production and imports less subsidies, and gross operating surplus -- the largest revisions usually occur to the gross operating surplus component. Revisions to the other two components are usually small. Nearly all revisions are the result of incorporating newly available source data that were unavailable at the time the earlier estimates were made.
Revisions to the most recent year’s estimates of value added by industry are largely the result of extrapolating newly available, revised estimates of corporate profits from the most recent annual update of the NIPAs, by industry, with Quarterly Financial Report (QFR) data published by the U.S. Census Bureau, as well as with other industry indicators developed from regulatory agency and public financial reports.
Revisions to the two earlier years’ estimates of value added by industry are largely the result of incorporating preliminary and then final (available about 2 years and 3 years, respectively, after their reference years) tax-based information on corporate profits from the Internal Revenue Service (IRS). These IRS tabulations provide critical source data for the National Income and Product Account’s (NIPAs) industry distributions of gross domestic income (GDI) which are used, in turn, to extrapolate industry estimates of value added for the AIAs.