Monthly
jobs numbers are based on two separate surveys, the household survey and the payroll survey. In the household survey, people are asked to describe their employment status, while the payroll survey aggregates payroll data from companies and public-sector employers. The household survey produces the percentage, but is the less reliable of the two measures because its sample size, about 60,000, is much smaller than the payroll survey, which covers 557,000 workplaces. The payroll survey provides the monthly number of jobs added or lost.
Even the revised numbers are still estimates based on survey data. So to correct for any errors that remain after revision, once a year the
BLS benchmarks its estimates, replacing the survey data with numbers from a comprehensive count of the unemployment insurance rolls. Those are the numbers that economic historians of the future will rely upon.
