Current Employment Survey Monthly Revisions
The Bureau of Labor Statistics (BLS) was established by An Act to Establish the Bureau of Labor in 1884. In 1913, it was renamed and moved inside the new Department of Labor by An Act to create a Department of Labor. This act was amended in 1930 to direct that BLS
shall also collect, collate, report, and publish at least once each month full and complete statistics of the volume of and changes in employment, as indicated by the number of persons employed, the total wages paid, and the total hours of employment, in the service of the Federal Government, the States and political subdivisions thereof, and in the following industries and their principal branches: (1) Manufacturing; (2) mining, quarrying, and crude petroleum production; (3) building construction; (4) agriculture and lumbering; (5) transportation, communication, and other public utilities; (6) the retail and wholesale trades; and such other industries as the Secretary of Labor may deem it in the public interest to include.
The BLS program that produces these estimates of month-to-month changes in employment by industry is the Current Employment Statistics (CES). The CES program attempts to balance competing needs for timely and accurate data by releasing "preliminary" survey-based estimates within three weeks of the employment period and then revising these estimates as BLS receives additional information.
Overview of CES Methods
CES estimates are based on a survey of nonfarm establishments and models of employment in establishments that cannot be surveyed. These survey-based estimates are released as preliminary estimates, typically within the following three weeks. They are revised over the following two months, with additional survey responses. They are revised again months later, with more complete information based on administrative (i.e., non-survey) data.
Survey
The CES survey, also known as the payroll survey or the establishment survey, is a monthly survey of approximately 121,000 businesses and government agencies. The employers surveyed are randomly selected to represent all nonfarm employers by state, industry, and employer size categories. After selection, employers are surveyed for at least two years. Each month, BLS asks them how many civilians were on their payroll during the pay period that included the 12th day of the month. Only employers that report these data for two months in a row are used in estimating month-to-month changes in employment.
Employment reports received by the last Friday of the month are incorporated into "first preliminary estimates" of employment change, which BLS usually releases on the first Friday of the next month. These estimates are based on 10-16 days of data collection, with the exact number of data collection days varying by month. Additional employment reports and corrections received in time for the following month's estimates are incorporated into revised, "second preliminary estimates." Employment reports and corrections received from more employers responding to the survey in time for a third month of estimation are incorporated into "third and final sample-based estimates" for each month.
The differences between the first preliminary estimates, second preliminary estimates, and third and final sample-based estimates are known as the CES Monthly Revisions.
Business Birth and Death Modeling
Some businesses are too new to be chosen for the CES survey. Other businesses do not answer the survey because they are no longer operating. Patterns of business openings and closings over the year vary by industry in predictable ways. BLS uses historical data to model employment changes due to business "births" and "deaths" and updates this model with new data every year.
This modeled component generally increases the accuracy of initial CES estimates. However, during periods of rapid economic change—both downturns and upturns in economic conditions—it can reduce the accuracy of initial estimates. This component has been part of all national-level CES employment estimates since 2003 (except during the COVID-19 pandemic, when use of the model was modified because it was clear business births and deaths were not following usual patterns). BLS researchers are studying potential improvements to the model.
Seasonal Adjustment
Some month-to-month changes are part of seasonal patterns, such as the opening and closing of ski resorts as the seasons change. Seasonal employment patterns differ by industry. BLS uses historical data to model these patterns and produces both seasonally adjusted and non-seasonally adjusted estimates of month-to-month employment changes.
Annual Benchmarking
BLS revises CES estimates of monthly employment changes based on additional data on overall civilian employment levels from the Unemployment Insurance tax system and other sources, which are available to BLS several months after CES survey responses. BLS uses these additional data to further revise, or benchmark, estimates of employment once each year. More information about benchmark revisions is available in CRS In Focus IF12827, Current Employment Survey Benchmark Revisions.
Reasons for Monthly Revisions
The primary reason for monthly revisions is that BLS receives survey responses and corrections from additional employers between the time that the first preliminary estimates are calculated and the time the third and final sample-based estimates are calculated.
The CES "collection rates" are defined as the fraction of employers that agreed to participate in the CES, are still in business, and responded to the survey sometime during the previous six months who respond to the CES in particular months. In 2024, the collection rate averaged 60.4% for first preliminary estimates, 89% for second preliminary estimates, and 90.9% for third and final survey-based estimates. The higher collection rates for second and third survey-based estimates show how much additional information BLS collects between first preliminary estimates and revised estimates.
Changes in these collection rates over time are shown in Figure 1. The first-closing collection rate increased steadily from 1981 to 2015, as BLS switched from mail response to telephone, web-based, and other electronic methods of data collection. However, first-closing collection rates have been declining since 2015. Declines in the percentage of these employers responding in time for their reports to be included in the second and third estimates (the "second and third closing collection rates") have been smaller.
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Source: BLS series CEU00000000C1, CEU00000000C2, and CEU00000000C3. |
Analyses by BLS researchers show no consistent patterns regarding which private sector employers report late—regardless of these employers' CES response methods, industries, sizes, geographic locations, or employee pay frequencies. However, government employers were often late reporters, and late reported employment changes and corrections contribute to revisions. In August 2025, BLS announced larger than usual monthly revisions to estimates of employment change in both May and June 2025; nearly half of these employment revisions were due to revisions in government employment (largely in local government education and state government education).
These collection rates are not the same as response rates. Response rates are the fraction of employers selected for the CES who agree to participate in the survey and provide data. CES response rates have fallen from about 58% before 2020 to 43% in 2024. Because the primary reason for monthly revisions is that BLS receives additional data from later CES responders, falling CES response rates are not the cause of monthly revisions. However, they may have more substantial impacts on CES Benchmark Revisions.
Magnitude of Monthly Revisions
Since 2003, when the CES began using its current methods, the average size of CES monthly revisions to seasonally adjusted employment change estimates has been a difference of 51,000 between the first preliminary estimates and the third and final survey-based estimates. Averaging positive revisions and negative revisions, the average revision was an increase of 9,000. The largest negative revision to the seasonally adjusted employment change estimates since 2003 was -672,000 in March 2020, as additional employers reported on how the COVID-19 pandemic disrupted their usual business; the largest positive revisions were 437,000 and 389,000 in November and December 2021. Figure 2 shows the pattern of revisions over time.
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Figure 2.Magnitude of CES Employment Revisions, Jan. 2000–June 2025 (in thousands) |
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Source: Seasonally adjusted third closing estimates relative to first closing estimates, in thousands, from https://www.bls.gov/web/empsit/cesnaicsrev.htm. |
Data on Monthly Revisions
BLS publishes tables of all revisions to overall nonfarm employment since 1979 at https://www.bls.gov/web/empsit/cesnaicsrev.htm. Detailed data on previous employment estimates by industry since 2003 are available at https://www.bls.gov/web/empsit/cesvininfo.htm.