A"Benchmark" is an annual revision process
in which monthly
labor force and payroll
employment by industry estimates are updated. Throughout the
year, employment by industry data are estimated based on sample data.
On an annual basis, when updated information becomes available
from detailed tax records, the employment by industry estimates are
revised. Tax record data are used through March; therefore, the
revision is referred to as the March Benchmark.
The labor force data series is also revised. The labor force statistics are calculated based on a number of data sources including the employment by industry data, Unemployment Insurance claims filed, and at the State level, data from the Current Population Survey (CPS), a survey of households. As these industry employment and CPS data are updated, so are the labor force statistics.
Because this review and update process is so extensive, and affects historical as well as current year data, the information is released in stages early each year. For more information on Benchmarking: U.S. Bureau of Labor Statistics.