BEA uses data from the latest month’s BLS payroll survey to estimate wages and salaries, the largest component of personal income. These early survey-based estimates are later revised to reflect more accurate administrative wage-and-salary data received 4½ months after the end of the reference quarter. Timely source data are also available for some other components of personal income, such as social security benefits.
Some analysts have asked about using withholding tax data. While withholding data are very timely and BEA uses them to supplement its estimates, the withholding data have not proved sufficiently reliable to use as a general-purpose extrapolator for wages and salaries. (See BEA FAQ: Can BEA use data on withheld taxes to improve its early estimates of wages and salaries?) Furthermore, withholding data do not cover the untaxed components of personal income, such as many government social benefit programs.