Annual Survey of Manufactures (ASM)

How the Data are Collected

The Annual Survey of Manufactures (ASM) is a sample survey of approximately 50,000 establishments. A new sample is selected at 5-year intervals beginning the second survey year subsequent to the Economic Census - Manufacturing. Since 2009 is the second survey year following the 2007 Economic Census, a new sample was selected based on the 2007 Economic Census - Manufacturing. The sample was supplemented by new establishments entering business in 2010 and 2009.

In 2007, there were approximately 328,500 active manufacturing establishments. For sample efficiency and cost considerations, the 2007 manufacturing population is partitioned into two groups:(1) establishments eligible to be mailed a questionnaire and (2) establishments not eligible to be mailed a questionnaire. The following is a description of the 2009 ASM sample design:

1. Establishments that are eligible to be sent a report form:
   This is defined as the mail stratum. It is comprised of larger single-location manufacturing companies and all manufacturing establishments of multi-location companies. The mail stratum is comprised of approximately 117,000 establishments. On an annual basis, the mail stratum is supplemented with large, newly active single-location companies identified from a list provided by the Internal Revenue Service (IRS) and new manufacturing locations of multi-location companies identified from the Census Bureau’s Company Organization Survey (COS).
   
   The 2009 ASM sample design is similar to the 2004-2008 sample design. The only significant change is the addition of a new certainty category. For most economic surveys, a number of units are included in the sample with certainty; i.e. their probability of selection for the survey is 1.00. Remaining units are generally assigned a probability that is consistent with their relative importance in the industry or other key aggregations. Establishments in the 2007 Economic Census - Manufacturing that satisfied any of the following criteria are included in the sample with certainty: (1) the total 2007 employment for the establishment is greater than or equal to 1,000; (2) the establishment is identified as one of the ten largest establishments within the industry (employment); (3) the establishment is classified within an industry with less than 20 establishments; (4) the establishment is classified in the computer or flat-glass industry; (5) the establishment is located within a state where there are less than 20 additional establishments in the same North American Industry Classification System (NAICS) group (NAICS group is defined as the set of NAICS industries that have the same first four digits); or (6) the establishment is one of the largest establishments in terms of cost of fuels used, cost of electricity used, end-of-year inventories, or end-of-year assets. Collectively, there are approximately 15,400 establishments that are selected with certainty. These establishments accounted for approximately 67 percent of the total value of shipments in the 2007 Economic Census - Manufacturing.
   
   Smaller establishments in the remaining portion of the mail stratum are sampled with probabilities ranging from .05 to 1.00. Each of the 471 industries and 1,384 product classes are considered to be a separate population. Using variable reliability constraints, each establishment within a given population is assigned an initial probability of selection that reflected its relative importance within the population. Establishments producing products in multiple product classes received multiple initial probabilities. The final probability of selection for a specific establishment is defined as the largest of their initial probabilities.
   
   This method of assigning probabilities is motivated by the Census Bureau's primary desire to produce reliable estimates of both product class and industry shipments. The high correlation between shipments and employment, value-added, and other general statistics assures that these variables will also be well represented. For sample selection purposes, each establishment is assigned to an industry stratum. Within each of the 471 industry strata, an independent sample is selected using the final probability of selection associated with the establishments classified within the stratum. A fixed-sample size methodology is used to assure that the desired sample size is realized.



2. Establishments not eligible to be sent a report form:
   1. This is defined as the nonmail stratum. The nonmail stratum consists of small- and medium-sized, single-establishment companies from the Economic Census - Manufacturing. The initial nonmail stratum of the 2009 sample contained approximately 211,000 single-establishment companies from the 2007 Economic Census - Manufacturing.
      
      The nonmail stratum is supplemented annually using the list of newly active single-location companies provided by the Internal Revenue Service (IRS). Data for establishments included in the nonmail stratum are estimated using information obtained from the administrative records of the IRS and Social Security Administration (SSA); and are included in the published ASM estimates. This administrative information, which includes payroll, total employment, industry classification, and physical location, is obtained under conditions which safeguard the confidentiality of both tax and census records.
   
   
   
   2. Nonemployers, i.e., firms subject to federal income tax, with no paid employees, are excluded from the ASM, as in previous years, unless they are known to employ manufacturing workers through a third party. Data for nonemployers are published in the annual Nonemployer Statistics series.

The report forms, frequently asked questions, and instructions used to collect information from establishments in the ASM are available at the Business Help Site.

The ASM files to review are available online.

Establishment Basis of Reporting

The Annual Survey of Manufactures (ASM) is conducted on an establishment basis. Reports are filed for those establishments selected in the sample. Companies engaged in distinctly different lines of activity at one location are requested to submit separate reports, if the plant records permit such a separation and if the activities are substantial in size. Estimates are based on the reports from a representative sample of manufacturing establishments. These estimates represent the portion of the manufacturing population accounted for by establishments with paid employees. Nonemployers are defined as out-of-scope of the ASM. The tables provide estimates for employment, plant hours, payrolls, value added by manufacture, capital expenditures, cost of materials, inventories, value of industry shipments, and fuels and electric energy consumed for most manufacturing industries.

The ASM excludes data for central administrative offices (CAOs). These would include separately operated administrative offices, warehouses, garages, and other auxiliary units that service manufacturing establishments of the same company. These data are published in a separate report series.

Reliability of the Data

All estimates produced in the Annual Survey of Manufactures (ASM) are subject to both sampling and nonsampling errors. Sampling error is inherent to all sample surveys and reflects the natural variability in the estimates that occurs because data are only collected from a subset of the population. The estimates are also subject to various types of nonsampling error. Examples of nonsampling error include measurement error and processing error. Nonsampling error is inherent to all surveys; including complete censuses.

1. Estimating Procedure. Most of the ASM estimates derived for the mail stratum are computed using a difference estimator. At the establishment level, there is a strong correlation between the current-year data values and the corresponding historical data values. At each level of aggregation, an estimate of the difference between the current reference period and the base reference period is computed for each item from the sample and added to the corresponding base-year values. This difference can be positive or negative. For the 2010 ASM estimates, the 2007 Economic Census - Manufacturing values serve as the base year.
   
   Due to these positive year-to-year correlations, estimates derived using this methodology are generally more reliable than comparable estimates developed from the current sample data alone. Estimates for the capital expenditures variables are not generated using the difference estimator because the year-to-year correlations are considerably weaker. The standard linear estimator is used for these variables.

   For the nonmail stratum, estimates for payroll are directly tabulated from the administrative-record data provided by the Internal Revenue Service (IRS) and the Social Security Administration (SSA). Estimates of the other data variables are developed from industry averages. Although the nonmail stratum contained approximately 190,000 individual establishments in 2010, it accounted for less than 7 percent of the estimate for total value of shipments at the total manufacturing level.

   Corresponding estimates for the mail and nonmail components are combined to produce the estimates included in this publication.




2. Data Qualifications. The estimates developed from the sample are likely to differ from the results of a complete canvassing of all eligible establishments in the population. The particular sample selected for the ASM is one of many probability samples that could have been selected under identical circumstances. Each of the possible samples would yield a slightly different set of results. The derived standard errors are measures of the variation of all the possible sample estimates around the true population statistic. Estimates with low standard errors are generally felt to be more accurate than those associated with high standard errors.

   Estimates of the standard errors are computed from the sample data for selected ASM statistics in this report. They are represented in the form of relative standard errors (the standard error divided by the corresponding estimate).

   In conjunction with its associated estimate, the relative standard error may be used to define confidence intervals (ranges that would include the comparable, complete-coverage value for specified percentages of all the possible samples).

   The complete-coverage value would be included in the range

   • From one standard error below to one standard error above the derived estimate for about two-thirds of all possible samples.
   • From two standard errors below to two standard errors above the derived estimate for about 19 out of 20 of all possible samples.
   • From three standard errors below to three standard errors above the derived estimate for nearly all samples.

   An inference that the comparable, complete-survey result would be within the indicated ranges would be correct in approximately the relative frequencies shown. Those proportions, therefore, may be interpreted as defining the confidence that the estimates from a particular sample would differ from complete-coverage results by as much as one, two, or three standard errors, respectively.

   For example, suppose an estimated total is shown at 50,000 with an associated relative standard error of 2 percent, that is, a standard error of 1,000 (2 percent of 50,000). There is approximately 67 percent confidence that the interval 49,000 to 51,000 includes the complete-coverage total, about 95 percent confidence that the interval 48,000 to 52,000 includes the complete-coverage total, and almost certain confidence that the interval 47,000 to 53,000 includes the complete-coverage total.

   In addition to the sample errors, the estimates are subject to various response and operational errors: errors of collection, reporting, coding, transcription, imputation for nonresponse, etc. These operational errors also would occur if a complete canvass were to be conducted under the same conditions as the survey. Explicit measures of their effects generally are not available. However, it is believed that most of the important operational errors are detected and corrected during the Census Bureau’s review of the data for reasonableness and consistency. The small operational errors usually remain. To some extent, they are compensating in the aggregated totals shown. When important operational errors are detected too late to correct the estimates, the data are suppressed or are specifically qualified in the tables.

   As derived, the estimated standard errors included part of the effect of the operational errors. The total errors, which depend upon the joint effect of the sampling and operational errors, are usually of the order of size indicated by the standard error, or moderately higher. However, for particular estimates, the total error may considerably exceed the standard errors shown. Any figures shown in the tables in this publication having an associated standard error exceeding 15 percent may be combined with higher level totals, creating a broader aggregate, which then may be of acceptable reliability
   

   .

Duplication in Cost of Materials and Value of Shipments

Data for cost of materials and value of shipments include varying amounts of duplication, especially at higher levels of aggregation. This is because the products of one establishment may be the materials of another. The value added statistics avoid this duplication and are, for most purposes, the best measure for comparing the relative economic importance of industries and geographic areas.

Value of Industry Shipments Compared with Value of Product Shipments

The Annual Survey of Manufactures (ASM) shows value of shipments data for industries and products. In the industry statistics tables and files, these data represent the total value of shipments of all establishments classified in a particular industry. The data include the shipments of the products classified in the industry (primary to the industry), products classified in other industries (secondary to the industry), and miscellaneous receipts (resales, contract receipts, repair work, etc.). Value of product shipments shown in the products statistics tables and files represent the total value of all products shipped that are classified as primary to an industry regardless of the classification of the producing establishment.

Disclosure

In accordance with federal law governing census reports (Title 13 of the United States Code), no data are published that would disclose the operations of an individual establishment or company. However, the number of establishments in a specific industry or geographic area is not considered a disclosure; therefore, this information may be released even though other information is withheld. Techniques employed to limit disclosure are discussed at: www.census.gov/econ/census07/www/methodology/disclosure.html

The disclosure analysis for statistics in the 2010 and 2009 data were performed at the field level, i.e., disclosure analysis was performed for each variable independent of other variables for that NAICS-based industry or product class. This differs from previous years' disclosure analysis, whereby disclosure suppressions were based upon the total value of shipments, with an independent disclosure analysis for capital expenditures. When data for a NAICS-based industry or product class are suppressed, these data still are included in higher-level totals.

Data Sets:

Sector 31: Annual Survey of Manufactures: General Statistics: Statistics for Industry Groups and Industries: 2010 and 2009

Sector 31: Annual Survey of Manufactures: Value of Products Shipments: Value of Shipments for Product Classes: 2010 and 2009

Sector 31: Annual Survey of Manufactures: Geographic Area Statistics: Statistics for All Manufacturing by State: 2010 and 2009

Sector 31: Annual Survey of Manufactures: Geographic Area Statistics: Supplemental Statistics for the United States and States: 2010 and 2009

PDF Publications: None

Back to Top